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Can Quantum-Mechanical Description of Physical Reality Be Considered Complete?
Abstract
In a complete theory there is an element corresponding to each element of reality. A sufficient condition for the reality of a physical quantity is the possibility of predicting it with certainty, without disturbing the system. In quantum mechanics in the case of two physical quantities described by non-commuting operators, the knowledge of one precludes the knowledge of the other. Then either (1) the description of reality given by the wave function in quantum mechanics is not complete or (2) these two quantities cannot have simultaneous reality. Consideration of the problem of making predictions concerning a system on the basis of measurements made on another system that had previously interacted with it leads to the result that if (1) is false then (2) is also false. One is thus led to conclude that the description of reality as given by a wave function is not complete.
... Qubit, which represents a two-dimensional quantum mechanical system, is a fundamental unit of quantum information. By increasing the number of qubits, it is also possible to describe entanglement, which is the most prominent quantum-mechanical phenomenon [1]. Entanglement is an essential ingredient of quantum teleportation, quantum computation, and quantum sensing. ...
... where the relative phase is also ignored as 2S1I configuration. Each state can be continuously converted to |S-I-I⟩ SI 1 I 2 = |000⟩ SI 1 I 2 as θ → 0 except W class. Through numerical analysis, we find that the probe state which minimizes the mean HB in W class is |ψ⟩ SI 1 ...
... This state is another representation of the SI-I state. Conversely, the state in this class which maximizes the mean HB is |ψ⟩ SI 1 ...
Quantum illumination is a protocol for detecting a low-reflectivity target by using two-mode entangled states composed of signal and idler modes. In this study, we extend the two-mode qubit states to three-mode qubit states, exploring the following configurations: (i) three signals, (ii) two signals and one idler, and (iii) one signal and two idlers. Each configuration considers various three-qubit states, such as GHZ state, W state, bipartite entangled states, and product states. We derive single-shot detection limits of the three-qubit states under white noise environment, evaluating the detection error probabilities for each configuration. We obtain that the performance is enhanced by the entanglement between signal and idler qubits, whereas it is degraded by the entanglement between signal qubits. In particular, the optimal probe state is not a maximally entangled state but a bipartite entangled state. Moreover, we show that the order of detection error probabilities is consistently certified by the quantum mutual information for the three-qubit probe states. Furthermore, we devote attention to whether this tendency maintains even in multipartite qudit states.
... The thought experiment proposed by Einstein, Podolsky and Rosen (EPR) in 1935 [1] and the subsequent proposal by Bell [2] continue to challenge the world view of students around the globe. When measuring the spin of entangled particles, EPR claimed that the 'Copenhagen' interpretation of quantum mechanics would lead to 'spooky action at a distance' and would therefore be untenable [1] [3]. ...
... The thought experiment proposed by Einstein, Podolsky and Rosen (EPR) in 1935 [1] and the subsequent proposal by Bell [2] continue to challenge the world view of students around the globe. When measuring the spin of entangled particles, EPR claimed that the 'Copenhagen' interpretation of quantum mechanics would lead to 'spooky action at a distance' and would therefore be untenable [1] [3]. EPR suggested that there must be 'hidden variables' that predetermine the outcome of all measurements. ...
... To the best of our knowledge this is a novel approach when preparing phase shifted EPR-Bell states, as we have seen no reports in the literature of such experiments with various phase shifts, setting , as shown below in Eqn. (1), to any angle between 0 and π. We report the results of polarization correlation experiments with some intriguing questions about how to interpret them, with future possible application in quantum information, communication and computation. ...
Inspired by previous studies and pioneers of the field, we present new results on an extensive EPR-Bell experiment using photons generated by parametric down conversion, where one of the photons is deliberately phase-shifted. Our experiments show some surprising results for particular angles of this phase shift.
... Quantum nonlocality is one of the most important properties of quantum mechanics. It was first pointed out by Einstein, Podolsky, and Rosen [1], highlighting conflicts between quantum mechanics and local realism. Later, Bell derived a statistical inequality, known as the Bell inequality, to certify nonlocality [2]. ...
... Similarly, we obtain C (1,2) ...
... When ϕ ∈ (0.424, π/4], there exists a mixed strategy that allows two Charlies to share the standard nonlocality. For each fixed value of ϕ within this range, the range of the parameter p can be easily calculated, 1 sin 2ϕ − 1 < p < 3 − 2 sin 2ϕ . ...
Bell nonlocality is a valuable resource in quantum information processing tasks. Scientists are interested in whether a single entangled state can generate a long sequence of nonlocal correlations. Previous work has accomplished sequential tripartite nonlocality sharing through unsharp measurements. In this paper, we investigate the sharing of tripartite nonlocality using only projective measurements and sharing classical randomness. For the generalized GHZ state, we have demonstrated that using unbiased measurement choices, two Charlies can share the standard tripartite nonlocality with a single Alice and a single Bob, while at most one Charlie can share the genuine tripartite nonlocality with a single Alice and a single Bob. However, with biased measurement choices, the number of Charlies sharing the genuine tripartite nonlocality can be increased to two. Nonetheless, we find that using biased measurements does not increase the number of sequential observers sharing the standard tripartite nonlocality. Moreover, we provide the feasible range of double violation for the parameters of the measurement combination probability with respect to the state.
... For that purpose, we first show why the uncertainty principle prevents measuring local, hidden variables [Heisenberg (1927)]. Then, we explain how the EPR paradox [Einstein et al. (1935)] tries to demand such variables, which started the research culminating in Bell's theorem. Finally, we derive Bell's inequality [Bell (1964)] and show how quantum mechanics seems to violate it. ...
... It could be that the observer effect disturbs the momentum of such a particle in some random manner when the position is measured. Therefore, in the Einstein-Podolsky-Rosen (EPR) paradox [Einstein et al. (1935)], the attempt has been made to construct a setup where the observer effect can apparently be circumvented such that position and momentum seem to be measurable simultaneously. This is done by considering two entangled particles which are far apart from each other. ...
... (2.280) So, quantum mechanics is truly complete. However, the authors of the EPR paper Einstein et al. (1935) were still right that something is missing. But it is not a modification of quantum mechanics but a true understanding by expressing quantum mechanics in the most natural way, which is complex field statistics. ...
We crack quantum physics.
... The description of the fundamental factors of nonrelavistic quantum had already been completed by von Neumann in his book Mathematische Grundlagen der Quantenmechanik in 1932, which was considered as an axiomatic paradigm of quantum mechanics following Hilbert's line [1][2][3]. However, Einstein, Podolsky and Rosen (EPR) and Schrodinger were the first who figured out a strange nature of quantum mechanics, which showed thatthe presence of composite system global states that are not the result of the states of separate subsystems [2]. ...
... The description of the fundamental factors of nonrelavistic quantum had already been completed by von Neumann in his book Mathematische Grundlagen der Quantenmechanik in 1932, which was considered as an axiomatic paradigm of quantum mechanics following Hilbert's line [1][2][3]. However, Einstein, Podolsky and Rosen (EPR) and Schrodinger were the first who figured out a strange nature of quantum mechanics, which showed thatthe presence of composite system global states that are not the result of the states of separate subsystems [2]. The phenomenon is also known as "entanglement". ...
... Photons are coherently absorbed in Bob's cavity, and the polarization of these particles is transferred onto the atom's internal state. As a result, the two atoms at Alice and Bob get somewhat entangled [2,8]. The last kind of method for the distribution of the entanglement is based on two atoms being excited at the same time. ...
Quantum mechanics is a field of physics that became important from the late 19th century to the start of the 20th century and its non-relativistic part seemed to be completed by von Neumann in 1932. However, the EPR paradox by Einstein, Podolsky and Rosen pointed out a strange feature of quantum mechanics known as quantum entanglement, which represented that people are unable to consider the existence of global states of composite system as a product of the states of separate subsystems. The phenomenon promotes to a further study of quantum and a new faster way of communication. The article introduces the discovery and the early research of the quantum entanglement, how the theory about the quantum entanglement was corrected, the fabrication of the entangled particles, and the application of the quantum entanglements phenomena to the quantum communication. The research aims to discuss the importance of the study of the quantum entanglement at current stage
... Quantum theory has been challenging the physics community for a century now. The question remains open of whether there exists an extension theory, as envisioned by Einstein, Podolsky, and Rosen (EPR) [1], which is able not only to predict the same statistical distributions as the Born rule for repeated experiments-they are observed in Nature with very high precision-but also to predict each individual measurement outcomes. ...
... • Einsteinian locality: no element of information propagates faster than light. 1 Determinism is derived from these two with a short argument made by Bell [2], thus the companion adjective "local-realist." ...
We show that causal contextuality scenarios are equivalent to a subset of the formerly published spacetime games, which generalize game theory to decisions arbitrarily located in Minkowski spacetime. This insight leads to certain constructs and proofs being shorter, simpler, and more intuitive when expressed in the spacetime game framework than in the causal contextuality scenario framework. This shows that the insights of both frameworks taken together can contribute positively to advancing the field of quantum foundations.
... Closely related to the concept of quantum coherence, no quantum correlation is viable without interference with respect to distinguishable alternatives of quantum states. Nowadays nonclassical correlations are invaluable resources for quantum information and quantum computation [1], but they emerged on the scene by raising one of the most important problems in the foundations of quantum theory [2,3] and, surprisingly, by providing the solution of the same [4,5]. Schrödinger introduced the expression entanglement for this first manifestation of quantum correlation [3]. ...
... In general, mixed states characterize the interaction between the system and its environment, and the study of their entanglement properties is not only more complicated than that of pure states, but lesser understood. Although the first entangled system found in physics was in a pure state [2], it is in one of the Bell states [4], shortly after mixed states were identified that also disrupt the foundations of quantum theory [21]. These states, named after Werner, can be modeled using hidden variables without violating the Bell inequalities, and find applications in a diversity of quantum entanglement subjects [22][23][24][25][26][27][28][29][30][31]. ...
We investigate entanglement in two‐qubit systems using a geometric representation based on the minimum of essential parameters. The latter is achieved by requiring subsystems with the same entropy, regardless of whether the state of the entire system is pure or mixed. The geometric framework is provided by a convex set 𝒮 that forms a right‐triangle, whose points are linked to the absolute value of just two of the coherences of the system under study. As a result, we find that optimized states of two qubits host pairs of identical populations while reducing the number of coherences involved, so they are X‐shaped. A geometric L L ‐measure of entanglement is introduced as the distance between the points in 𝒮 that represent entangled states and the closest point that defines separable states. It is shown that L L reproduces the results of the Hill‐Wootters concurrence C C , so that C C can be interpreted as a distance‐like entanglement measure. However, unlike C C , the measure L L also distinguishes the rank of states. The universality of the two‐qubit X‐states ensures the utility of our geometric model for studying entanglement of two‐qubit states in any configuration. To show the applicability of our approach far beyond time‐independent cases, we construct a time‐dependent two‐qubit state, traced out over the complementary components of a pure tetra‐partite system, and find that its one‐qubit states share the same entropy. The entanglement measure results bounded from above by the envelope of the minima of such entropy.
... Beta waves (13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30) Hz) ...
... Examples: During meditation or a mental break. (13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30). State: Alertness, concentration, intense mental activity. ...
Exploring Love as a Fundamental Dimension of Reality: A New Interdisciplinary Vision In this paper, I propose a groundbreaking theory that views love not just as an emotion, but as a fundamental dimension of reality, alongside space and time. By integrating perspectives from physics, cuantum physics, biology, neuroscience, psychology, and philosophy, this theory opens new horizons in understanding how love (emotions) influences not only our physical reality but also collective consciousness and human health. The central question driving this research is: What would the world look like if love were a fundamental force governing not only emotions but also our physical and energetic interactions? And what impact would this have on our relationships, and even the scientific paradigm itself? My paper discusses: • The concept of love as an energetic dimension: Drawing analogies with the electromagnetic spectrum and the body’s bioelectric coherence, it suggests that love can be viewed as an organising force that influences reality on multiple levels. • The impact of love on health and collective consciousness: How love generates bioelectric coherence, affecting both physical and emotional health, and synchronizing biological rhythms between individuals to create a collective field of empathy. • Emotions’ involvement in healing and enhancing social connections. This work is not just a theoretical exercise, but an invitation to reconsider how we perceive love and its impact on our entire experience as human beings. The proposed theory could revolutionise fields such as mental health, emotional education, and even global peace. This research is just the first step in a broader journey that could fundamentally change the way we understand not only love but the entire reality we live in. If you are passionate about the intersection of science and emotion, philosophy and biology, I invite you to explore this paper and join the conversation about the dimension of the feelings in our universe. A new dimension of reality: the dimension of feelings © 2024 by Ileana Constantinescu is licensed under Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International. To view a copy of this license, visit https://creativecommons.org/licenses/by-nc-nd/4.0/
... In 1935, Einstein, Podolsky, and Rosen (EPR) found that quantum mechanics lacks a very important property known as the element of reality and locality [20]. Thus, they concluded that quantum mechanics is an incomplete theory. ...
... Einstein together with Podolsky and Rosen recognized that quantum theory allows a particular type of correlation (later known as entanglement) between two distant parts of a system [20]. ...
In recent years considerable progress has been made towards developing a general theory of quantum entanglement. In particular, criteria to decide whether a given quantum state is entangled are of high theoretical and practical interest. This problem is additionally complicated by the existence of bound entanglement, which are weak entangled states and hard to detect. In this thesis, we have worked on the characterization of bipartite and tripartite entanglement. We have established a few separability criteria that successfully detect Negative Partial Transpose (NPT) as well as Positive Partial Transpose (PPT) entangled states. Although the topic of detection of entanglement has been extensively studied in the literature through many approaches, the majority of these criteria are not physically realizable. This means that they are well accepted in the mathematical language but cannot be implemented in a laboratory setting. In this thesis, we propose some theoretical ideas to realize these entanglement detection criteria experimentally.
... In quantum mechanics, the spin of an electron is one of the most important physical observables to demonstrate the essence of quantum theory. For instance, measurement of the spin of an electron always obtains two possible values, spin-up or spin-down, along the direction of the measuring magnetic field; To describe the dynamics of an electron with spin, multicomponents wave functions in the Schrödinger-Pauli equation are needed; In investigating the quantum entanglement phenomenon, the singlet state of an electron pair is often used as example to illustrate conceptual challenges such as in the Bohm version EPR thought experiment [1,2], or to verify the violation of Bell inequality [3]. However, these important quantum features are either not derived from first principles or still have conceptual difficulties. ...
... First we consider the initial condition described by the joint probability density functions given by (61). This initial condition can be further decomposed such that half of the chance that the joint probability densityp z, 1 ...
Quantum theory of electron spin is developed here based on the extended least action principle and assumptions of intrinsic angular momentum of an electron with random orientations. The novelty of the formulation is the introduction of relative entropy for the random orientations of intrinsic angular momentum when extremizing the total actions. Applying recursively this extended least action principle, we show that the quantization of electron spin is a mathematical consequence when the order of relative entropy approaches a limit. In addition, the formulation of the measurement probability when a second Stern-Gerlach apparatus is rotated relative to the first Stern-Gerlach apparatus, and the Schrödinger-Pauli equation, are recovered successfully. Furthermore, the principle allows us to provide an intuitive physical model and formulation to explain the entanglement phenomenon between two electron spins. In this model, spin entanglement is the consequence of the correlation between the random orientations of the intrinsic angular momenta of the two electrons. Since spin orientation is an intrinsic local property of the electron, the correlation of spin orientations can be preserved and manifested even when the two electrons are remotely separated. The entanglement of a spin singlet state is represented by two joint probability density functions that reflect the orientation correlation. Using these joint probability density functions, we prove that the Bell-CHSH inequality is violated in a Bell test. To test the validity of the spin-entanglement model, we propose a Bell test experiment with time delay. Such an experiment starts with a typical Bell test that confirms the violation of the Bell-CHSH inequality but adds an extra step that Bob’s measurement is delayed with a period of time after Alice’s measurement. As the time delay increases, the test results are expected to change from violating the Bell-CHSH inequality to not violating the inequality.
... One can see that the terms «mixed state -density matrix» partially correspond to the terms «mixture -statistical operator» used by von Neumann and Schrödinger. 6 Thus, in the world-widely approved textbook, which represented the mature quantum-mechanical paradigm, the principal difference between closed, completely separate initial components and relevant parts of complex quantum systems was recognized definitely. The tools to consider and describe these related but principally different entities were fixed finally. ...
... There is no an unavoidable necessity to use the idea of entanglement or related terminology in the mature quantum paradigm. At the same time, there is no categorical prohibition to all these to surrogate the pair «mixed state -density matrix» in order to grasp wholeness of non- 6 Today it is recognized that factually von Neumann introduced density matrix in order to develop quantum statistical mechanics and theory of quantum measurements. In contrast, Landau was motivated by impossibility of describing a subsystem of a complex quantum system by a state vector (see, e.g., [16]). ...
Idea of quantum entanglement is discussed in the context of debate about the Einstein-Podolsky-Rosen thought experiment and some theoretical studies of quantum systems. It is noted that Schrödinger invented this idea in 1935 in order to fix some features of the quantum-mechanical description of two systems with temporary interaction. However, he did not grasp essence of these features really. In view of the concepts of mixture and statistical operator proposed by von Neumann and adopted by Schrödinger in 1936, it is argued that the idea of entanglement and related terminology are not necessary in quantum mechanics. One can use this idea and terms «entanglement» etc. as «visual» surrogates for the «mixture-statistical operator» pair. Deeper comparative analysis of several theoretical works by Schrödinger, von Neumann, and Landau showed that the modeling of non-trivial complex quantum systems as quasi-classical aggregates has been gradually overcome. Instead, wholeness of such quantum systems was actually recognized step by step. Thus, wholeness is immanent not only to quantum phenomena, as Niels Bohr had argued, but also to the quantum systems themselves, objectively. The pair «mixture-statistical operator» and especially the pair «mixed state-density matrix» similar to it appear to be adequate tools to comprehend and describe wholeness of diverse quantum reality. It is insisted, it is advisable to understand the surrogate idea of entanglement and relevant terminology in the same sense. In mature quantum paradigm, they are possible but not necessary theoretical tools to grasp wholeness of reality. Respectively, acceptable understanding of quantum entanglement must be based on recognition of quantum wholeness. The clarified understanding of quantum entanglement, as well as Bohr's substantiation of wholeness of quantum phenomena, demonstrates irreducibili-ty of the Universe to any quasi-classical aggregate. Moreover, all this supports the view of the Universe as real wholeness, which rational holism intends to grasp. It is concluded, contemporary rational holism has clear potential to replace the hitherto widespread worldview in the spirit of Democritus and pure analytical methodology of knowledge. Keywords: quantum entanglement, Einstein-Podolsky-Rosen thought experiment , quantum wholeness, wholeness of the Universe, rational holism.
... Recent results from ATLAS [8] and CMS [9] have provided the first evidence of entanglement in top-quark pair production at the LHC. This follows earlier observations of Bell inequality violations [10]-fundamental tests of quantum correlations rooted in the Einstein-Podolsky-Rosen completeness paradox [11]-in particle physics using B-meson decays at LHCb and Belle II [12]. These results demonstrate that quantum correlations persist at energies over 12 orders of magnitude [3,13,14,15] higher than those in typical laboratory entanglement experiments. ...
We investigate quantum correlations in Higgs-boson decays using CMS open data at = 8 TeV, incorporating realistic detector effects. By reconstructing the polarization density matrix of the two-boson system and evaluating the Collins-Gisin-Linden-Massar-Popescu (CGLMP) Bell operator , we quantify entanglement in the ZZ state. Our analysis shows that of signal events violate the Bell inequality , indicating strong quantum correlations, while only of non-resonant continuum background events exhibit such a violation. These results demonstrate the feasibility of testing fundamental quantum mechanics at high energy colliders.
... However, multi-partite-based entanglement distribution is discussed briefly in Section 7.2. In particular, the quantum internet is concerned with the distribution of a special two-qubit entangled system, named EPR pair [7] or Bell state [8]. An example of Bell state is as follows: ...
As the field of the quantum internet advances, the necessity for a comprehensive guide to navigate its complexities has become increasingly crucial. Quantum computing, a more established relative, shares foundational principles with the quantum internet; however, distinguishing between the two is essential for further development and deeper understanding. This work systematically introduces the quantum internet by addressing fundamental questions: Why is it important? What are its core components? How does it function? When will it be viable? Who are the key players? What are the challenges and future directions? Through elucidating these aspects along with a comprehensive introduction to the basic concepts, we aim to provide a clear and accessible overview of the quantum internet, facilitating the groundwork for future innovations and research in the field.
... The EPR article [42] and later Bell's theorem [43] have raised the question of locality in quantum mechanics. Bell proved that realistic quantum mechanical interpretations that impose that there is a single outcome from experiments, as in the Copenhagen interpretation (CI) or dBB theory, either include or imply an instantaneous interaction at a distance, or are superdeterministic. ...
In the de Broglie Bohm pilot-wave theory and the many-worlds interpretation, unitary development of the quantum state is universally valid. They differ in that de Broglie and Bohm assumed that there are point particles with positions that evolve in time and that our observations are observations of the particles. The many-worlds interpretation is based on the fact that the quantum state can explain our observations. Both interpretations rely on the decoherence mechanism to explain the disappearance of interference effects at a measurement. From this fact, it is argued that for the pilot-wave theory to work, circumstances must be such that the many-worlds interpretation is a viable alternative. However, if this is the case, the de Broglie–Bohm particles become irrelevant to any observer. They are truly hidden. The violation of locality and the corresponding violation of Lorenz invariance are good reasons to believe that dBB particles do not exist.
... Penerapan teknologi digital dalam sistem manajemen pendidikan sangat penting untuk memastikan daya saing di pasar layanan pendidikan (Zhuravel et al., 2022). Pemeringkatan universitas berfungsi sebagai metode yang sah untuk menganalisis daya saing lembaga pendidikan, menekankan pentingnya pendidikan berkualitas dan pengetahuan sebagai keunggulan kompetitif (Einstein, Podolsky, & Rosen, 1935). Pengelolaan bauran pemasaran yang efektif, meliputi unsur-unsur seperti produk, pembiayaan, lokasi, promosi, sumber daya manusia, dan fasilitas, dapat menumbuhkan keunggulan kompetitif dan meningkatkan daya saing penerimaan peserta didik baru. ...
The aim of this research is to analyze training management development strategies that can help increase the competitiveness of educational institutions which focuses on the concept of training management development, training management development strategies in increasing the competitiveness of educational institutions, and the challenges. This research uses library research methods. The research results show that the concept of training management development is a systematic approach to planning, organizing, implementing and evaluating training and development programs to improve individual and organizational performance which includes: planning training, organizing training, implementing training, evaluating training and controlling training. Meanwhile, the development strategy is through comprehensive analysis of training needs, flexibility and responsiveness to change, development of quality teaching staff, use of technology in learning, partnerships with industry and communities, as well as ongoing monitoring and evaluation. The challenges are limited resources, rapid environmental changes, diverse needs of staff and employees, limited time and commitment, as well as various other factors that complicate the planning, implementation and evaluation of training programs.
... 1 Introduction Einstein et al. (1935) famously argued that Quantum Mechanics (QM) cannot be regarded as a complete theory-there should exist some additional ("hidden" in the sense of not being captured by the quantum state) variables that explain in a local way the correlations that occur in quantum experiments. A major contribution to the investigation of theories postulating such variables (called "hidden variable theories", in short "HVTs") was made by Bell (1964), who proposed a general framework in which one can analyse all such theories at once. ...
Bell's conclusion from his famous inequality was that any hidden variable theory that satisfies Local Causality is incompatible with the predictions of Quantum Mechanics (QM) for Bell's Experiment. However, Local Causality does not appear in the derivation of Bell's inequality. Instead, two other assumptions are used, namely Factorizability and Settings Independence. Therefore, in order to establish Bell's conclusion, we need to relate these two assumptions to Local Causality. The prospects for doing so turn out to depend on the assumed location of the hidden states that appear in Bell's inequality. In this paper, I consider the following two views on such states: (1) that they are states of the two-particle system at the moment of preparation, and (2) that they are states of thick slices of the past light cones of measurements. I argue that straightforward attempts to establish Bell's conclusion fail in both approaches. Then, I consider three refined attempts, which I also criticise, and I propose a new way of establishing Bell's conclusion that combines intuitions underlying several previous approaches.
... We may describe more, but we are not required to do so. See Bohr's observation on this point [18] in response to the EPR paper [32]. ...
In quantum mechanics time is generally treated as a parameter rather than an observable. For instance wave functions are treated as extending in space, but not in time. But from relativity we expect time and space should be treated on the same basis. What are the effects if time is an observable? Are these effects observable with current technology? In earlier work we showed we should see effects in various high energy scattering processes. We here extend that work to include bound states. The critical advantage of working with bound states is that the predictions are significantly more definite, taking the predictions from testable to falsifiable. We estimate the time dispersion for hydrogen as .177 attoseconds, possibly below the current threshold for detection. But the time dispersion should scale as the 3/2 power of the principle quantum number n. Rydberg atoms can have n of order 100, implying a boost by a factor of 1000. This takes the the time dispersion to 177 attoseconds, well within reach of current technology. There are a wide variety of experimental targets: any time-dependent processes should show effects. Falsification will be technically challenging (due to the short time scales) but immediate and unambiguous. Confirmation would have significant implications for attosecond physics, quantum computing and communications, quantum gravity, and the measurement problem. And would suggest practical uses in these areas as well as circuit design, high speed biochemistry, cryptography, fusion research, and any area involving change at attosecond time scales.
... They share the same quantum state, and when one part is defined, the other is realised accordingly. It was this fact that fascinated Einstein, Podolsky and Rosen, and which made them doubt the correctness of the theory of quantum mechanics [25]. Nowadays, this phenomenon has been extensively tested and practically corroborated [26,27], proving its foundations solidly and correctly describing human understanding of the small elements that make up reality. ...
This article introduces QScratch, a novel educational tool designed to introduce fundamental quantum concepts and principles. It is an extension of the high-level block-based visual programming language Scratch, developed by the MIT Media Lab. The quantum concepts taught are presented in a simple and illustrative, yet rigorous way. The selection of topics and their adaptation for this project has been made taking into account the huge complexity of the subject, developing specific intuitive blocks to model the quantum behaviours of superposition, entanglement and measurement. A pilot study carried out with a group of 68 students has demonstrated the validity of the software developed as a tool for introducing complex quantum physics concepts. Thus, the proposed tool complements the original Scratch tool, advancing in the construction of Science, Technology, Engineering and Mathematics (STEM) tools that facilitate the introduction of quantum concepts to everyone.
... Introduction.-Entanglement has attracted both great interest and considerable controversy since the early days of quantum mechanics, most famously expressed by the "EPR paradox" which posits that quantum mechanics is inconsistent with local realism [1,2]. Today however, entanglement is well established as an empirical fact, and is regarded as a necessary resource for achieving quantum advantage in next-generation quantum technologies [3,4]. ...
In understanding strongly correlated quantum systems, quantifying the non-Gaussian nature of interparticle correlations is invaluable. We show that, for a uniform quantum gas, there exists a natural connection between non-Gaussian correlations and the generation of momentum-space entanglement. Furthermore, this entanglement can be directly measured in an experiment using time-of-flight techniques. To prototype our method, we numerically study entanglement generation in a degenerate Bose gas following a quench to the unitary regime, where Gaussian and non-Gaussian correlations are generated sequentially in time.
... It is worth mention-ing that the entanglement among macroscopic objects has been extensively studied due to its fundamental testing of quantum mechanics and potential applications in quantum information processing [2][3][4], and thus many researches are focused on the preparation and realization of macroscopic entanglement in various quantum systems [5][6][7][8][9]. With the deepening of the research, Einstein-Podolsky-Rosen (EPR) steering, a quantum correlation stronger than quantum entanglement, was initially proposed by Schrödinger in 1935 [10] to address the famous EPR paradox [11] and was later reformulated by Wiseman et al. [12], who elucidated the hierarchy among Bell nonlocality, EPR steering and quantum entanglement. Compared to quantum entanglement, EPR steering describes the nonlocality ability of a system to influence the state of another entangled system through local measurements. ...
We present a scheme to generate nonreciprocal entanglement and asymmetric steering between an atomic ensemble and a magnon based on Kerr nonlinearity of magnon in an yttrium iron garnet sphere. In particular, a cavity optomagnonic system is under our consideration, where the optical cavity couples with an ensemble of N two-level atoms, and meanwhile nonlinearly interacts with the magnon mode via optomagnonic coupling. The results demonstrate that the steady-state macroscopic quantum correlations including magnon-atomic ensemble entanglement and Einstein–Podolsky–Rosen steering could be obtained via strongly driving the cavity mode. More importantly, tuning the direction of the static magnetic field leads to a positive or negative magnon Kerr coefficient, which leads to a corresponding shift in magnon frequency and thus induces the nonreciprocity of entanglement. Furthermore, the one-way steering between magnon and atomic ensemble is also shown via properly choosing the coupling strengths and effective Kerr parameters. Our work could have potential applications in the preparation of macroscopic quantum states and be applied to construct long-distance quantum networks.
... Early studies of quantum nonlocality focused on symmetric correlations, including entanglement [1] and Bell nonlocality [2][3][4], where the observers in the system have symmetric states. In 1935, Schrödinger proposed the Einstein-Podolsky-Rosen (EPR) steering to discuss the EPR paradox [5][6][7], highlighting that EPR steering is a type of asymmetric quantum nonlocality. EPR steering has the property that one observer influences the state of another observer by performing local measurements, and its asymmetric quantum nonlocality has attracted widespread attention [8,9]. ...
We investigate quantum steering of Dirac field for different types of Bell states in Schwarzschild–de Sitter (SdS) spacetime that has a black hole event horizon (BEH) and a cosmological event horizon (CEH). We find that fermionic steerability from Bob to Alice is greater than fermionic steerability from Alice to Bob, while bosonic steerability exhibits the opposite behavior in SdS spacetime. These different properties between fermionic and bosonic steering arise from the differences between Fermi–Dirac statistics and Bose–Einstein statistics. We also find that the Hawking effect of the black hole decreases fermionic steerability. However, the Hawking effect of the expanding universe can enhance fermionic steerability, which differs from the properties of quantum steering in single-event horizon spacetime. Interestingly, we can indirectly protect quantum steering by using appropriate types of Bell states in multi-event horizon spacetime. These conclusions are helpful to guide the task of processing relativistic quantum information for quantum steering in SdS spacetime.
... Despite his reservations, the predictions of quantum mechanics challenged this intuition. The EPR (Einstein-Podolsky-Rosen) experiment, proposed by Einstein himself in collaboration with Boris Podolsky and Nathan Rosen in 1935 [14], sought to demonstrate that quantum mechanics was incomplete precisely because it permitted the existence of nonlocal correlations. In his own words, "I cannot believe that God plays dice with the universe," reflecting his disagreement with the probabilistic and nonlocal nature of quantum predictions. ...
In this work, we study nonlocal differential equations with particular focus on those with reflection in their argument and piecewise constant dependence. The approach entails deriving the explicit expression of the solution to the linear problem by constructing the corresponding Green's function, as well as developing a novel formula to delineate the set of parameters involved in the analyzed equations for which the Green's function exhibits a constant sign. Furthermore, we demonstrate the existence of solutions for nonlinear problems through the utilisation of diverse results derived from fixed-point theory. The aforementioned methodology is specifically applied to the linear problem with periodic conditions for , proving several existence results for the associated nonlinear problem and precisely delimiting the region where the Green's function has a constant sign. % when . The equations studied have the potential to be applied in fields such as biomedicine or quantum mechanics. Furthermore, this work represents a significant advance, as it is the first time that equations with involution and piecewise constant arguments have been studied together.
... In quantum mechanics, rather than taking a beam of the particles impinging on the beam splitter we consider a quantum state of a single particle/photon. The quantum state itself is a subject of philosophical interest as well as its application aspect also explores many insights in the understanding of physics [14,15]. Further this single particle state is now used to manipulate the information and further used in many quantum informatics tasks [20,21]. ...
The information is carried through binary number 0 and 1 in classical communication which represents the high/low values of the voltage/current in
the system. Contrary to it quantum Mechanics possess the superposition as
well as entangled states and these quantum states can be used to transfer
the information. Here, in the work we will construct an N- Mach-Zehnder interferometer (N-MZI) setup through which two parties can interact or share
information. The astonishing feature of this setup is that communication
can be done even in the absence of any photon in the channel and termed
as counterfactual communication. Acknowledging M.S Zubairy for his book
and paper on counterfactual communication for getting the maximum idea
from his book to redraw the figures.
... The concept of nonlocality in quantum mechanics has been a subject of intense study and debate since the seminal work of Einstein, Podolsky, and Rosen in the 1930s [1]. In 1964, John Bell established experimentally testable criteria, known as Bell's inequality [2]. ...
The study of quantum nonlocality sharing has garnered significant attention, particularly for two-qubit and three-qubit entangled systems. In this paper, we extend the investigation to n-qubit Greenberger-Horne-Zeilinger (GHZ) systems, analyzing nonlocality sharing under unbiased unsharp measurements. Employing the Seevink and Svetlichny inequalities, we explore both unilateral and multilateral sequential measurement scenarios. In the unilateral scenario, we derive the range for which an observer's multiple copies can share genuine n-partite nonlocality with single copies of the remaining parties. In the multilateral scenario, we identify the maximum number of independent observers on m sides who can share genuine n-partite nonlocality with other parties. A crucial aspect of our results is that all findings stem from a measurement strategy where each sequential observer utilizes unbiased unsharp measurements. As a specific case, for the four-qubit maximally entangled GHZ state, we demonstrate that at most two copies of an observer (e.g., Alice) can share nonlocality in the unilateral sequential measurement scenario. However, in the multilateral scenario, no additional sharing is possible compared to the unilateral case. This finding highlights the significance of unsharp measurements in optimizing the recycling of qubits for generating quantum nonlocality.
... Still, a decisive blow to the hidden-variable programme [71] was dealt by Bell's theorem [27], and the much more recent loophole-free verification of stronger than classical correlations in Bell experiments [59,20,86,169], that is, of correlations described in terms of "classical states" -in the form of probability measures -on a "classical state space" -in the form of a measurable space, under the additional assumption of relativistic causality [182]. The study of Bell inequality violations [39] and the theory of quantum entanglement [106] form the cornerstone of quantum information science, and lie behind the promise of a (second) technological revolution based on quantum effects. ...
Contextuality is a key distinguishing feature between classical and quantum physics. It expresses a fundamental obstruction to describing quantum theory using classical concepts. In turn, when understood as a resource for quantum computation, it is expected to hold the key to quantum advantage. Yet, despite its long recognised importance in quantum foundations and, more recently, in quantum computation, the mathematics of contextuality has remained somewhat elusive - different frameworks address different aspects of the phenomenon, yet their precise relationship often is unclear. In fact, there is a glaring discrepancy already between the original notion of contextuality introduced by Kochen and Specker on the one side [J. Math. Mech., 17, 59, (1967)], and the modern approach of studying contextual correlations on the other [Rev. Mod. Phys., 94, 045007 (2022)]. In a companion paper [arXiv:2408.16764], we introduce the conceptually new tool called ``context connections'', which allows to cast and analyse Kochen-Specker (KS) contextuality in new form. Here, we generalise this notion, and based on it prove a complete characterisation of KS contextuality for finite-dimensional systems. To this end, we develop the framework of ``observable algebras". We show in detail how this framework subsumes the marginal and graph-theoretic approaches to contextuality, and thus that it offers a unified perspective on KS contextuality. In particular, we establish the precise relationships between the various notions of ``contextuality" used in the respective settings, and in doing so, generalise a number of results on the characterisation of the respective notions in the literature.
... In this sense, quantum mechanics (QM) has demonstrated extraordinary predictive power when modeling the behavior of microscopic particles, providing also tools for technological boosts in fields like communication [1][2][3][4][5][6], computation [7][8][9][10][11], imaging [12][13][14][15][16][17], hypothesis testing [18][19][20][21], metrology [22][23][24][25][26] and sensing [27][28][29][30][31][32][33][34], but a large debate is still running in the scientific community about its foundational aspects. Particularly relevant is the investigation of nonlocal traits of quantum correlations among spatially-separated parties [35], a research field which originated in 1935 with the Einstein-Podolsky-Rosen (EPR) paradox [36]. In 1964, J. S. Bell demonstrated how locality constrains the correlations between measurements on a bipartite system [37], proving that QM can exceed such a bound and, therefore, proving that its predictions are incompatible with those of any (classical) Local Hidden Variable Theory (LHVT) [37,38]. ...
Quantum correlations, like entanglement, represent the characteristic trait of quantum mechanics, and pose essential issues and challenges to the interpretation of this pillar of modern physics. Although quantum correlations are largely acknowledged as a major resource to achieve quantum advantage in many tasks of quantum technologies, their full quantitative description and the axiomatic basis underlying them are still under investigation. Previous works suggested that the origin of nonlocal correlations is grounded in principles capturing (from outside the quantum formalism) the essence of quantum uncertainty. In particular, the recently-introduced principle of Relativistic Independence gave rise to a new bound intertwining local and nonlocal correlations. Here we test such a bound by realizing together sequential and joint weak measurements on entangled photon pairs, allowing to simultaneously quantify both local and nonlocal correlations by measuring incompatible observables on the same quantum system without collapsing its state, a task typically forbidden in the traditional (projective) quantum measurement framework. Our results demonstrate the existence of a fundamental limit on the extent of quantum correlations, shedding light on the profound role of uncertainty in both enabling and balancing them.
... The term local refers back to Einstein's theory of local hidden variables, which was one attempt to explain the type of randomness that occurred in quantum experiments [41]. If Einstein's theory had been correct, then when two parties performed experiments in separated, physically isolated labs on a shared quantum state, any density that they would be able to produce would be local. ...
We present an overview of the theory of nonlocal games and how games induce algebras. These algebras have been used to separate various sets of quantum correlations, leading to the resolution of problems of Connes, Kirchberg and Tsirelson. We survey the theory of various families of games, including games arising from graph isomor-phisms, graph colorings, and systems of equations.
... Of particular importance for our work is superdense coding. If we assume that the two users each hold one qubit of an Einstein-Podolsky-Rosen (EPR) pair [5], one user can perform local operations on its qubit to create an arbitrary maximally entangled state for the pair. Subsequently, this user sends its qubit to the other user. ...
We introduce a generalization of one-way superdense coding to two-way communication protocols for transmitting classical bits by using entangled quantum pairs. The proposed protocol jointly addresses the provision of entangled pairs and superdense coding, introducing an integrated approach for managing entanglement within the communication protocol. To assess the performance of the proposed protocol, we consider its data rate and resource usage, and we analyse this both in an ideal setting with no decoherence, and in a more realistic setting where decoherence must be taken into account. In the ideal case, the proposal offers a 50% increase in both data rate and resource usage efficiency compared to conventional protocols. Even when decoherence is taken into consideration, the quantum protocol performs better as long as the decoherence time is not extremely short. Finally, we present the results of implementing the protocol in a computer simulation based on the Netsquid framework. We compare the simulation results with the theoretical values.
... Quantum entanglement [1], Schrödinger famously said, is the characteristic trait of quantum mechanics which enforces its entire departure from the classical line of thought [2,3]. ...
Understanding the relationship between various different forms of nonclassicality and their resource character is of great importance in quantum foundation and quantum information. Here, we discuss a quantitative link between quantum entanglement and the anomalous/nonclassical nonreal values of Kirkwood-Dirac (KD) quasiprobability, in a bipartite setting. We first construct an entanglement monotone for a pure bipartite state based on the nonreality of the KD quasiprobability defined over a pair of orthonormal bases in which one of them is a product, and optimizations over these bases. It admits a closed expression as a Schur-concave function of the state of the subsystem having a form of nonadditive quantum entropy. We then construct a bipartite entanglement monotone for generic quantum states using the convex roof extension. Its normalized value is upper bounded by the concurrence of formation, and for two-qubit systems, they are equal. We also derive lower and upper bounds in terms of different forms of uncertainty in the subsystem quantified respectively by an extremal trace-norm asymmetry and a nonadditive quantum entropy. The entanglement monotone can be expressed as the minimum total state disturbance due to a nonselective local binary measurement. Finally, we discuss its estimation using weak value measurement and classical optimization, and its connection with strange weak value and quantum contextuality.
... The view, Bohr and Heisenberg as representatives, is known as the Copenhagen annotation, which supports the completeness of quantum mechanics. The other side, Einstein and Schrödinger as representatives, supports local realism and sharply criticizes Copenhagen's annotation, which was reflected in two renowned works in 1935, namely the Schrödinger cat paradox [1] and the Einstein Podolsky Rosen paradox [2]. The term "entangled state" was first introduced in Schrödinger's article on the cat paradox; an entangled state is a superposition state that cannot be expressed as the direct product of quantum states with each subsystem. ...
Two kinds of phenomena with the same essence may be correlative. Exploring this correlation can help us generate new ideas. Light can carry three types of angular momentum: The rotating electromagnetic field with circularly polarized will produce spin angular momentum (SAM); The vortex light with helical wavefronts will carry intrinsic orbital angular momentum (IOAM); Light, not traveling through the coordinate origin, will carry extrinsic orbital angular momentum (EOAM). The interaction between SAM and EOAM will produce a spin Hall effect of light. The interaction between SAM and IOAM will lead to mutual conversion between them. SAM and EOAM, as well as SAM and IOAM, can also form spin–orbit entangled states. Therefore, the spin–orbit interaction and corresponding entangled states of light must have some correlations. This work studied the relationship between the spin Hall effect and the spin–orbit entangled state, and the relationship between the conversion efficiency of spin–orbit angular momentum and the spin–orbit entangled state. This work can provide new enlightenment to the study of entangled states, which can help the cross-disciplinary application of quantum entanglement with other knowledge.
... accounting for entanglement generation time of the longest physical link in the path (t e j ), entanglement swapping operations (t s j ) and, time of propagation of the Bell measurement at the furthest node (correction) (t c j ) and, if needed, purification time (t p j ). Next, the network capacity C(r i ) or throughput refers to the number of entangled states that can be shared between the requested end nodes in r i per unit time, in this case we use Einstein-Podolsky-Rosen [4] pairs (EPRs) per second. Definition 2. The capacity of the EBN network is C(r i ) = 1 c j cj min (δ,tj) , where the denominator accounts for the fact that the processing overhead can exceed the persistence time δ, and δ would take its place as the process would terminate in that case. ...
Entanglement-based networks (EBNs) enable general-purpose quantum communication by combining entanglement and its swapping in a sequence that addresses the challenges of achieving long distance communication with high fidelity associated with quantum technologies. In this context, entanglement distribution refers to the process by which two nodes in a quantum network share an entangled state, serving as a fundamental resource for communication. In this paper, we study the performance of entanglement distribution mechanisms over a physical topology comprising end nodes and quantum switches, which are crucial for constructing large-scale links. To this end, we implemented a switch-based topology in NetSquid and conducted a series of simulation experiments to gain insight into practical and realistic quantum network engineering challenges. These challenges include, on the one hand, aspects related to quantum technology, such as memory technology, gate durations, and noise; and, on the other hand, factors associated with the distribution process, such as the number of switches, distances, purification, and error correction. All these factors significantly impact the end-to-end fidelity across a path, which supports communication between two quantum nodes. We use these experiments to derive some guidelines towards the design and configuration of future EBNs.
... This problem can be tackled by verifying Bell nonlocality 7 or Einstein-Podolsky-Rosen (EPR) steering 8 between distant users. The violation of Bell inequality ensures the quantum random number generation (QRNG) in a device-independent manner [9][10][11][12][13] , where the user's devices are all untrusted. ...
Randomness is an essential resource and plays important roles in various applications ranging from cryptography to simulation of complex systems. Certified randomness from quantum process is ensured to have the element of privacy but usually relies on the device’s behavior. To certify randomness without the characterization for device, it is crucial to realize the one-sided device-independent random number generation based on quantum steering, which guarantees security of randomness and relaxes the demands of one party’s device. Here, we distribute quantum steering between two distant users through a 2 km fiber channel and generate quantum random numbers at the remote station with untrustworthy device. We certify the steering-based randomness by reconstructing covariance matrix of the Gaussian entangled state shared between distant parties. Then, the quantum random numbers with a generation rate of 7.06 Mbits/s are extracted from the measured amplitude quadrature fluctuation of the state owned by the remote party. Our results demonstrate the first realization of steering-based random numbers extraction in a practical fiber channel, which paves the way to the quantum random numbers generation in asymmetric networks.
... We simulate three configurations for entanglement generation between two ground nodes (Alice and Bob). The three configurations that we assume here are shown in Fig. 5. First, as shown in Fig. 5(a), we consider a simple scenario of a central node (Charlie), generating an entangled (pair also called EPR pair due to historical reasons [128]) and sending one qubit each to both Alice and Bob through optical fiber links. The total distance between Alice and Bob is d km. ...
Satellite communications (SatComs) have recently been through a renaissance, both technologically and entrepreneurially. Ambitious plans have already come into fruition with the operation of low-Earth orbit (LEO) constellations including thousands of satellites and supported by state of the art but proprietary technologies, such as active antenna arrays and intersatellite links (ISLs). In this context, this article aims to provide a forward-looking vision of use cases and a deep dive into technological enablers that will be prominent in space communications beyond 2030. In parallel, it motivates how open standards can play a role in delivering affordable communication services in space. Starting from the 5G plans for nonterrestrial networks, we provide a survey and roadmap toward artificial intelligence (AI)-supported satellite systems, space-enabled quantum networks, and joint communications and positioning (JCAP) for space missions and interplanetary exploration.
... The challenges to classical realism posed by quantum mechanics are encapsulated in the Einstein-Podolsky-Rosen (EPR) paradox [11] and addressed through Bell's theorem, which rigorously demonstrates the incompatibility of local hidden variables with quantum predictions [15]. Bell's ideas, further elaborated in Speakable and Unspeakable in Quantum Mechanics [16], and the Kochen-Specker theorem [19], underscore the contextuality and non-classical nature of quantum systems. ...
This is a work of hard physical philosophy, where Quantum Perspectivism is shown to function as both an interpretation of quantum mechanics and a physical model for understanding Nietzsche's perspectivism. This framework combines quantum logic, the principle of complementarity, and contextuality to examine how perspectives construct reality. In this model, measurements correspond to Perspectives and Meta-Perspectives, represented as Boolean subalgebras and Hilbert sub-lattices within the Hilbert lattice, respectively. The Hilbert lattice itself is reinterpreted as Jung's Unus Mundus, a unified ontological reality. A metaphysical observation, made by a metaphysical observer, of a given system (World) is identified with the set of all corresponding meta-perspectives in the Hilbert lattice/Unus Mundus, the ocean of reality. Perspectives, likened to islands in this ocean, correspond to single measurements of a system, capturing the logical structure of observed properties. Meta-perspectives, analogous to continents, represent the synthesis of multiple measurements, providing a broader yet inherently incomplete understanding of the system. This structure emphasizes the complementarity and contextual dependencies of measurements while exposing the limitations of classical objectivity in the quantum domain. Advocating for a perspectival view of both the world and truth, Quantum Perspectivism unites quantum mechanics and Nietzschean philosophy into a cohesive framework for exploring the interplay between consciousness, observation, and reality.
Disclaimer: We acknowledge the assistance of GPT-4, an AI language model, in drafting this manuscript. The author retains full responsibility for all intellectual content, research, final edits, and creative decisions presented in this work. Artwork created using DALL-E, offering only a re-imagined visualization of the key concepts featured in this work.
... As early as 1935, Einstein, Podlsky and Rosen Proposed a special state for two particles (known as the EPR state), commonly referred to as an entangled state, which cannot be written as the direct product of states of two subsystems [1]. Quantum entanglement is the non-local quantum correlation, indicating that it remains unaffected by the distance between the two subsystems and persists regardless of how far apart they are. ...
The spin-12 three-leg antiferromagnetic Heisenberg spin ladder is studied under open boundary condition (OBC) and cylinder boundary condition (CBC), using the density matrix renormalization group and matrix product state methods, respectively. Specifically, we calculate the energy density, entanglement entropy, and concurrence while discussing the effects of interleg interaction J2 and the alternating coupling parameter gamma on these quantities. It is found that the introduction of gamma can completely reverse the concurrence distribution between odd and even bonds. Under CBC, the generation of the interleg concurrence is inhibited when gamma=0, and the introduction of gamma can cause interleg concurrence between chains 1 and 3, in which the behavior is more complicated due to the competition between CBC and gamma. Additionally, we find that gamma induces two types of long-distance entanglement (LDE) in the system under OBC: intraleg LDE and inter-leg one. When the system size is sufficiently large, both types of LDE reach similar strength and stabilize at a constant value. The study indicates that the three-leg ladder makes it easier to generate LDE compared with the two-leg system. However, the generation of LDE is inhibited under CBC which the spin frustration exists. In addition, the calculated results of energy, entanglement entropy and concurrence all show that there are essential relations between these quantities and phase transitions of the system. Further, we predict a phase transition point near gamma=0.54 under OBC. The present study provides valuable insights into understanding the phase diagram of this class of systems.
... Entanglement is a quantum-mechanical property with no classical equivalent, exhibiting stronger-than-classical correlations shared by two or more objects. Since its initial discovery [1][2][3], entanglement has evolved from a subject for scientific debate to a transformative resource that enables capabilities beyond the limits of classical physics [4]. Entanglement now a cornerstone of a broad range of fields, including quantum computing [5], quantum communication [6,7], quantum sensing [8][9][10][11], and quantum imaging [12], offers a pathway to surpass the fundamental limits of classical technologies arising from quantum mechanical fluctuations [4]. ...
Optical frequency combs have emerged as a cornerstone for a wide range of areas, including spectroscopy, ranging, optical clocks, time and frequency transfer, waveform synthesis, and communications. However, quantum mechanical fluctuations of the optical carrier impose fundamental performance limits on the precision of traditional classical laser frequency combs, particularly in their use for interferometry and spectroscopy. Entanglement, as a quintessential quantum resource, allows for surpassing the fundamental limits of classical systems. Here, we introduce and experimentally demonstrate entangled dual-comb spectroscopy (EDCS) that surmounts the fundamental limits of classical DCS. EDCS builds on tailored entangled spectral structures of the frequency combs, enabling simultaneous detection of all comb lines below the standard quantum limit of classical DCS. Applying EDCS in gas detection, we achieve a 2.6 dB enhancement in signal-to-noise ratio and a 1.7-fold reduction in integration time over classical DCS, rendering EDCS particularly suited for dynamic chemical and biological sensing, where fast, precise measurements subject to power constraints are required. EDCS represents a new paradigm for quantum frequency combs, underscoring their prospects in a plethora of applications in precision metrology, spectroscopy, and timekeeping.
... Ethereum accommodates several clients including Go-Ethereum (Geth) and Parity. Geth and Parity provide JSON-RPC interfaces to interact with the Ethereum blockchain, with Parity being better equipped to retrieve data due to the improved interface design, ensuring accurate and efficient data retrieval [8], [9], [10], [11], [12], [13]. ...
The world is witnessing a noticeable increase in financial exchange in digital currencies such as Bitcoin, Ethereum, and others, as transactions in electronic markets have begun to rise recently, which increases the difficulty of maintaining security and trust in decentralized financial systems that use distributed databases and the technologies that interact with them in Ethereum networks, blockchain, etc. This study presents a hybrid model based on the PyCaret library and includes 12 machine learning classifiers, with the aim of identifying fraudulent activities in Bitcoin transactions and enhancing the security of Ethereum networks and blockchain technology. The results reveal the effectiveness of different models in identifying fraudulent activities on the Ethereum network through a comprehensive performance comparison. The classifiers that showed the highest accuracy scores, which ranged from 0.9814 to 0.9862, were the Random Forest classifier, the visual gradient boosting machine, and the additive tree classifier. It is important to note that both Gradient Boosting Classifier and K Neighbors Classifier performed well, with accuracies above 0.96 and AUC scores above 0.99. However, some models, such as Naive Bayes, showed lower accuracy and AUC scores, suggesting that they have limitations in terms of accurately detecting fraudulent transactions. These results highlight the importance of choosing appropriate machine learning models for fraud detection tasks in general, with ensemble techniques such as Extra Trees and Random Forest showing great promise in this regard.
In orthodox Standard Quantum Mechanics (SQM) bases and factorizations are considered to define quantum states and entanglement in relativist terms. While the choice of a basis (interpreted as a measurement context) defines a state incompatible to that same state in a different basis, the choice of a factorization (interpreted as the separability of systems into sub-systems) determines wether the same state is entangled or non-entangled. Of course, this perspectival relativism with respect to reference frames and factorizations precludes not only the widespread reference to quantum particles but more generally the possibility of any rational objective account of a state of affairs in general. In turn, this impossibility ends up justifying the instrumentalist (anti-realist) approach that contemporary quantum physics has followed since the establishment of SQM during the 1930s. In contraposition, in this work, taking as a standpoint the logos categorical approach to QM —basically, Heisenberg’s matrix formulation without Dirac’s projection postulate— we provide an invariant account of bases and factorizations which allows us to to build a conceptual-operational bridge between the mathematical formalism and quantum phenomena. In this context we are able to address the set of equivalence relations which allows us to determine what is actually the same in different bases and factorizations.
Bell's inequalities established in 1964 and the experiments carried out by Alain Aspect in 1982 on entangled photons made it possible to refute all theories with local hidden variables and to confirm the predictions of quantum mechanics.
This article has several objectives:
-To show that, if quantum mechanics is correct, then there is a superluminal influence between entangled photons,
-To propose an explanation and a possible mechanism of this superluminal influence by the gravitons field of the Dynamic Medium of Reference theory,
-To propose an experiment allowing a superluminal transmission of information,
-To propose an expression of the superluminal speed of gravitons and a link with vacuum energy and dark energy by a new law of physics:
the Evacuum/Edark ratio is equal to the Duniverse/(c.tPlanck) ratio squared.
Entanglement is a fundamental resource for various optical quantum information processing (QIP) applications. To achieve high-speed QIP systems, entanglement should be encoded in short wavepackets. Here we report the real-time observation of ultrafast optical Einstein–Podolsky–Rosen correlation at a picosecond timescale in a continuous-wave system. Optical phase-sensitive amplification using a 6-THz-bandwidth waveguide-based optical parametric amplifier enhances the effective efficiency of 70-GHz-bandwidth homodyne detectors, mainly used in 5G telecommunication, enabling its use in real-time quantum state measurement. Although power measurement using frequency scanning, such as an optical spectrum analyser, is not performed in real time, our observation is demonstrated through the real-time amplitude measurement and can be directly used in QIP applications. The observed Einstein–Podolsky–Rosen states show quantum correlation of 4.5 dB below the shot-noise level encoded in wavepackets with 40 ps period, equivalent to 25 GHz repetition—10³ times faster than previous entanglement observation in continuous-wave systems. The quantum correlation of 4.5 dB is already sufficient for several QIP applications, and our system can be readily extended to large-scale entanglement. Moreover, our scheme has high compatibility with optical communication technology such as wavelength-division multiplexing, and femtosecond-timescale observation is also feasible. Our demonstration is a paradigm shift in accelerating accessible quantum correlation—the foundational resource of all quantum applications—from the nanosecond to picosecond timescales, enabling ultrafast optical QIP.
This chapter considers mathematics, with a special emphasis on geometry, as combining mathematical and artistic thinking. By artistic thinking I do not refer to aesthetic aspects of mathematics or mathematical aspects of art or aesthetics, which subjects are only marginally addressed in the article. Instead, I focus on creative aspects of mathematics as the invention of new concepts, theories, or fields. As my subtitle indicates, this argument, beginning with the term “poetics,” follows that of Aristotle’s Poetics [Peri poietike~s], a treatise on ancient Greek poetry, the title of which is derived from the ancient Greek word poeien meaning “making,” putting something together. Aristotle’s Poetics is about how literature is made or composed. Aristotle did not apply the term poetics to mathematics and did not consider mathematics in this way, focusing instead, in his other works, on logical aspects of mathematics. By contrast, I argue, under the heading of the composition principle, that, as a creative endeavor, mathematics is primarily defined by its compositional nature, rather than by its logical or calculational aspects, essential as the latter are. Of course, while compositional, mathematics is not the same as literature and art. In particular, the poetics of mathematics is the poetics of concepts, which play a more limited role in literature and art, and ally mathematics or mathematical sciences, such as physics, more with philosophy. Two other principles define mathematics, as well as science, in the present view: the continuity principle (found in literature and art as well) and the unambiguity principle (not necessary in literature and art). The chapter introduces yet another principle in considering the nature of reality, the “reality without realism” (RWR) principle, which in the case of mathematics, where the primary reality considered in mental, becomes the “ideality without idealism” (IWI) principle.
Hegel’s philosophy of nature (Naturphilosophie) is impossible to separate from the rest of his system, in which nature is shown as a reflection of the idea (Idee) as presented in the logic (in the Enzyklopädie der philosophischen Wissenschaften). The system composed by logic, nature, and spirit, represents a dialectical relation in which logic as the universal, nature as the particular, and spirit as the singular, mediate through one another and develop as immanent and constitutive parts of the system as a whole. Yet, the goal of the philosophy of nature is not unrelated to a philosophy of science in the contemporary sense. The latter aims to solve (among other problems) the problem of dualism between the conceptual scheme/the world and the demarcation of science (and knowledge), where the crucial difference is that the Hegelian philosophy of nature benefits from having an answer to these in the form of the absolute idea (die absolute Idee). In a contemporary sense, the constitution of these problematics would follow an abductive reasoning where the Hegelian idea (Idee) would solve these crucial problems for philosophy of science. The following paper will attempt to provide some guiding points for such a project and suggest the assumptions necessary for its development, with the sole purpose of underscoring the similarities and differences between the Hegelian philosophy of nature and a contemporary philosophy of science.
Hyperentangled swapping is a quantum communication technique that involves the exchange of hyperentangled states, which are quantum states entangled in multiple degrees of freedom, to enable secure and efficient quantum information transfer. In this paper, we demonstrate schematics for the hyperentanglement swapping between separate pairs of neutral atoms through the mathematical framework of atomic Bragg diffraction, which is efficient and resistant to decoherence, yielding deterministic results with superior overall fidelity. The utilised cavities are in a superposition state and interact with the incoming atoms off‐resonantly. Quantum information carried by the cavities is swapped through resonant interactions with two‐level auxiliary atoms. We also discuss entanglement swapping under a delayed‐choice scenario and provide a schematic generalisation covering multiple‐qubit scenarios. Finally, we introduce specific experimental parameters to demonstrate the experimental feasibility of the scheme. image
In correspondence with the modal interpretations of quantum mechanics, Lombardi and Castagnino (2008) and da Costa, Lombardi and Lastiri (2013) have proposed an ontology of bundles of possible intrinsic properties for quantum mechanics, focused mainly on the issues of quantum contextuality and indistinguishability. Corresponding to the interpretation known as "relational quantum mechanics" (Rovelli, 1996), two ontologies based on relations have been proposed. Laura Candiotto (2017) advocates for a radical metaphysics of relations, considered by the author as an instance of the so-called "ontic structural realism". Alternatively, Andrea Oldofredi (2021) proposes an ontology of bundles of relations, considered by the author as an instance of the so-called "moderate structural realism". Since the 1980s, the topic of quantum entanglement has led several authors (Teller, Healey, Howard, Esfeld) to defend that quantum mechanics involves a form of holism. It has been argued that the holism of quantum mechanics supports the metaphysical thesis known as "priority monism" (Schaffer, 2010a). In this article, an ontology of quantum mechanics is proposed in which the properties of quantum systems have both a modal and a relational character. As a result, a holistic ontology of quantum mechanics is obtained, which is an instance of priority monism and moderate structural realism.
We analyze the interference of individual photons in a linear-optical setup comprised of two overlapping Mach–Zehnder interferometers joined via a common beam splitter. We show how, in this setup, two kinds of standard interference effects—namely, single-photon Mach–Zehnder interference and two-photon Hong–Ou–Mandel interference—interfere with one another, partially canceling each other out. This new perspective, along with the overall pedagogical exposition of this work, is intended as an intuitive illustration of why quantum effects can combine nontrivially and, moreover, of the fundamental notion that quantum interference happens at measurement. This work can serve as a bridge to more advanced quantum mechanical concepts. For instance, analyses of this setup in terms of entanglement have a rich history and can be used to test the predictions of quantum mechanics versus local realism (e.g., as in Hardy's Paradox).
This Element presents the main attempts to account for causation as a metaphysical concept, in terms of 1) regularities and laws of nature, 2) conditional probabilities and Bayes nets, 3) necessitation between universals and causal powers, 4) counterfactual dependence, 5) interventions and causal models, and 6) processes and mechanisms. None of these accounts can provide a complete reductive analysis. However, some provide the means to distinguish several useful concepts of causation, such as total cause, contributing cause, direct and indirect cause, and actual cause. Moreover, some of these accounts can be construed so as to complement each other. The last part presents some contemporary debates: on the relation between grounding and causation, eliminativism with respect to causation in physics, the challenge against 'downward' causation from the Closure and Exclusion principles, robust and proportional causation, and degrees of causation. This title is also available as Open Access on Cambridge Core.
Artykuł niniejszy jest polemiką z niektórymi tezami sformułowanymi w pracy Sabine Hossenfelder Czy Wszechświat myśli? I inne ważne pytania nauki. Podano argumenty, że 1) twierdzenie o realnym istnieniu przeszłości, teraźniejszości i przyszłości jest tylko jedną z możliwych filozoficznych interpretacji czasoprzestrzeni szczególnej teorii względności, a teza o obiektywnym upływie czasu jest możliwa do pogodzenia z fizyką współczesną; 2) determinizm jest istotnie ograniczony przez probabilistyczny charakter jednej z fundamentalnych teorii fizyki współczesnej jaką jest mechanika kwantowa; 3) podejście redukcjonistyczne jest istotnie ograniczone przez teorię chaosu deterministycznego, w której zachowanie układów fizycznych jest opisywane przez nieliniowe równania różniczkowe, a także przez sytuację poznawczą w mechanice kwantowej.
In this paper, we review the concept and criterion of quantum entanglement in detail, review Bell’s inequality and Bell’s theorem, and introduce the historical experiment verification work on quantum entanglement. According to the physical view of EBSF we have proposed, the physical picture of quantum entanglement is analyzed in detail. We propose that: the invalidity of CHSH inequality means that the local realism — this logic of physics is only applicable to the physical level of matter particles, and is not applicable to quantum mechanics based on quantum states; quantum entanglement is an essential feature of QSS, and quantum entanglement mainly exists in quantum systems containing QSS. In the quantum system composed of QSS, because it is in the physical basic state of the completely symmetric quantum superfluid, mapped to the current space-time — Euclidean space —, “action at a distance” exists; the failure of CHSH inequality means that a quantum system (physical level) composed of QSS does not have Lorentz invariance and cannot be mathematically treated by the so-called QED or QCD field theory; a quantum system is composed of QSS whose space is a kind of quantum topology space; topological space evolves into Hilbert space, which evolves into present-day space (including classical space and general relativistic space); the space-time of the early universe is a kind of quantum topological space-time in condensed matter physics, and today’s space-time is embedded during certain stage of the evolution and condensation of the universe. However, we are confident that the effect of the QSS field (with quantum entanglement) on the existing QED and QCD quantum fields is weak under normal physical conditions.
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