Muhammad Suhail Zubairy

Texas A&M University | TAMU · Department of Physics and Astronomy

Hydrogen is the most dominant atom in the universe and is considered the main component of baryonic matter. Thus far, the quantum features of the unbounded hydrogen atoms in the background of the universe and the possibility of emerging unique quantum effects, such as entanglement on the cosmological scale, have not been considered. In this work, w...

We present a scheme for achieving broadband complete reflection by constructing photonic bandgap via collective atom-atom interaction in a one-dimensional (1D) waveguide quantum electrodynamics (QED) system. Moreover, we propose several strategies to further expand the ultrahigh reflection windows, including increasing the number of atoms with sepa...

In this work we investigate quantum interference in a four-level atom coupled to a negative index meta-material (NIMM) anisotropic plasmonic environment that supports both TE and TM polarized surface plasmons (SP). The analysis confirms the creation of the anisotropic environment and two dipoles can interfere with each other even if they are ort...

Gaussian states with nonclassical properties such as squeezing and entanglement serve as crucial resources for quantum information processing. Accurately quantifying these properties within multimode Gaussian states has posed some challenges. To address this, we introduce a unified quantification: the “classical-nonclassical polarity,” represented...

Cat states, as an important resource in the study of macroscopic quantum superposition and quantum information applications, have garnered widespread attention. To date, preparing large-sized optical cat states has remained challenging. We demonstrate that, by utilizing interaction-free measurement and the quantum Zeno effect, even a fragile quantu...

In this study, we explore the breaking of time-reversal symmetry in a scalable cavity quantum electrodynamics (QED) lattice. Such a lattice consists of triangular cells of three cavities coupled to a two-level atom. We synthesize artificial magnetic fields to enable the chiral transfer of photons by sinusoidally modulating the cavity frequencies. C...

We study the emission of a single-photon by a two-level emitter inside an atomic cavity consisting of two atomic mirrors coupled to a one-dimensional waveguide. With proper atomic separations, we realize a frequency comb as well as spectrum narrowing in the waveguide with the symmetric setting, and also unidirectional spectrum narrowing with asymme...

The notion of wave–particle duality remains one of the most debated subjects in the history of quantum physics. The most famous debate on the subject occurred between Bohr and Einstein. In this work, we revisit the wave–particle duality in the Bohr–Einstein debate from the viewpoint of the recently established duality-entanglement relation. We show...

It is well-known that the precision of a phase measurement with a Mach-Zehnder interferometer employing strong classic light can be greatly enhanced with the addition of weak nonclassical light. In the context of quantifying nonclassicality, the amount by which a nonclassical state can enhance precision in this way has been termed its ’metrological...

A deterministic preparation method for large-amplitude optical Schr\"odinger-cat state is proposed. The key ingredient is to entangle an atom buried in a single-side cavity with a large-amplitude coherent light pulse. To achieve this purpose, a multiple reflection Michelson interferometer is used. The light pulse can go back and forth inside the in...

The direct counterfactual quantum-communication protocol involving double-chained Mach-Zehnder interferometers requires a single-photon input. Here, we show that even with multiphoton light sources, including a strong coherent light source as input, the counterfactual communication can be achieved with success probability approaching unity in the i...

Enhancing quantum entanglement is important for many quantum information processing applications. In this paper, we consider a protocol for entanglement enhancing in a two-mode squeezed vacuum state (TMSVS), attained based on photon subtraction, photon catalysis, and photon addition. Central to such an operation is the task of mixing and detecting...

Enhancing quantum entanglement is important for many quantum information processing applications. In this paper, we consider a protocol for entanglement enhancing in a two-mode squeezed vacuum state (TMSVS), attained based on photon subtraction, photon catalysis, and photon addition. Central to such an operation is the task of mixing and detecting...

We develop a method based on the cross-spectrum of an intensity-modulated CW laser, which can extract a signal from an extremely noisy environment and image objects hidden in scattering media. We theoretically analyzed our scheme and performed the experiment by scanning the object placed in between two ground glass diffusers. The image of the objec...

In this paper we demonstrate competitive Zeno physics in the dissipative Jaynes-Cummings model. The mechanism relies on Zeno coexistence between the single-mode field and the environment. We show that the Zeno suppression of coherent evolution predicted by the standard Jaynes-Cummings model can dramatically fail in the presence of the dissipative e...

Photonic crystals based on graphene plasmons are highly tunable and can accurately control photonic transmission at nanoscale. In this work, the transfer matrix method (TMM) is introduced to study graphene plasmonic crystal (GPC) with periodic surface conductivity in the case of normal incidence. The introduction of TMM after considering the abnorm...

The chiral transfer of quantum information in a metal nanoring network is presented. A system of three metal nanorings coupled to a two-level quantum dot enables the chiral transport of quantum states by breaking the time-reversal symmetry, which provides a platform for chiral quantum information processing in nanorings. The direction of the chiral...

Quantum sensors, offering novel sensing and imaging technologies beyond the capabilities of any classical device, enable harnessing new technologies from atomic clocks and nanoscale microscopy to gravitational wave detection and delicate biological measurements. We consider the performance of W-type quantum states as the probe for the networked qua...

We study the decay of a single-photon pulse inside a cavity consisting of two atomic mirrors coupled to a one-dimensional waveguide. The finesse of the cavity can be increased with proper choice of coupling strength, cavity length, spontaneous decay rate, and separation between atoms. The loss rate of a single-photon pulse inside the cavity can be...

The direct counterfactual quantum communication protocol involving double chained Mach-Zehnder interferometers requires a single photon input. Here, we show that even with multiphoton light sources, including a strong coherent light source as inputs, the counterfactual communication can be achieved with success probability approaching unity in the...

We find that stimulated Raman excitation of an atom by a two-photon pulse can be enhanced by orders of magnitude if the photons are simultaneously frequency correlated and spatially anti-correlated. That is correlated photon pair must have an inherent time delay between its constituent photons.

Wave-particle duality is a bizarre feature at the heart of quantum mechanics which refers to the mutually exclusive dual attributes of quantum objects as the wave and the particle. Quantum eraser presents a counterintuitive aspect of the wave-particle duality. In this work, we show that quantum eraser can be quantitatively understood in terms of th...

We find that stimulated Raman excitation of an atom by a two-photon pulse can be enhanced by orders of magnitude if the photons are simultaneously frequency correlated and spatially anticorrelated. That is, a correlated photon pair must have an inherent time delay between its constituent photons. This counterintuitive feature is a manifestation of...

Wave-particle duality is a bizarre feature at the heart of quantum mechanics which refers to the mutually exclusive dual attributes of quantum objects as the wave and the particle. Quantum eraser presents a counterintuitive aspect of the wave-particle duality. In this paper, we show that quantum eraser can be quantitatively understood in terms of t...

Entanglement is an essential ingredient for building a quantum network that can have many applications. Understanding how entanglement is distributed in a network is a crucial step to move forward. Here we study the conservation and distribution of Gaussian entanglement in a linear network using a new quantifier for bipartite entanglement. We show...

We propose a computational ghost imaging (CGI) scheme using customized pink noise speckle pattern illumination. By modulating the power spectrum distribution of the speckles, we generate speckle patterns with a significant positive spatial intensity fluctuation correlation. We experimentally reconstruct images using our synthesized speckle patterns...

We present a novel method, to our knowledge, to synthesize non-trivial speckle patterns that can enable sub-Rayleigh second-order correlation imaging. The speckle patterns acquire a unique anti-correlation in the spatial intensity fluctuation by introducing the blue noise distribution on spatial Fourier power spectrum to the input light fields thro...

Entanglement is an essential ingredient for building a quantum network that can have many applications. Understanding how entanglement is distributed in a network is a crucial step to move forward. Here we study the conservation and distribution of Gaussian entanglement in a linear network using a new quantifier for bipartite entanglement. We show...

Nonclassical states enable metrology with a precision beyond that possible with classical physics. Both for practical applications and to understand non-classicality as a resource, it is useful to know the maximum quantum advantage that can be provided by a nonclassical state when it is combined with arbitrary classical states. This advantage has b...

The transmission of a two-level quantum emitter in its ground state through a graphene nanosheet is investigated. The graphene plasmons (GPs) field distribution, especially the opposite orientations of the vertical electric field components on the two sides of the graphene nanosheet, produces a significant nonadiabatic process during the interactio...

We present a novel method to synthesize non-trivial speckles that can enable superresolving second-order correlation imaging. The speckles acquire a unique anti-correlation in the spatial intensity fluctuation by introducing the blue noise spectrum to the input light fields through amplitude modulation. Illuminating objects with the blue noise spec...

We derive a generalized master equation for multiphoton pulses interacting with multiple emitters in a waveguide-quantum electrodynamics system where the emitter frequency can be modulated and the effects of nonguided modes can also be considered. Based on this theory, we can calculate the real-time dynamics of an array of interacting emitters driv...

Exploring enhanced nonlinear optics based on electromagnetically induced transparency (EIT) has always been one of the striking issues in cavity quantum electrodynamics. However, it is not clear whether the validity of EIT in enhancing nonlinear processes is universal. In this paper we demonstrate an efficient frequency conversion scheme via Autler...

Quantifying nonclassicality of a bosonic mode is an important but challenging task in quantum optics. Recently, a nonclassicality measure based on the concept of operational resource theory has been proposed [W. Ge, K. Jacobs, S. Asiri, M. Foss-Feig, and M. S. Zubairy, Phys. Rev. Res. 2, 023400 (2020)], which shows several crucial properties as a r...

We derive a generalized master equation for multiphoton pulses interacting with multiple emitters in a waveguide-quantum electrodynamics system where the emitter frequency can be modulated. Based on this theory, we can calculate the real-time dynamics of the collective interacting emitters driven by an incident photon pulse which can be vacuum, coh...

Continuous-variable quantum key distribution (CV-QKD) provides an effective way to obtain the high secret key rate, but is limited by practical techniques. To overcome this limitation, we investigate the performance of CV-QKD protocols when non-Gaussian operations are applied to both sides of the channels, including photon subtraction and addition,...

Quantifying nonclassicality of a bosonic mode is an important but challenge task in quantum optics. Recently, the first nonclassicality measure based on the concept of operational resource theory has been proposed [Phys. Rev. Research 2, 023400 (2020)], which shows several crucial properties as a resource for quantum metrology. Here we apply the me...

The nonclassical properties of quantum states are of tremendous interest due to their potential applications in future technologies. It has recently been realized that the concept of a resource theory is a powerful approach to quantifying and understanding nonclassicality. To realize the potential of this approach, one must first find resource theo...

Mode-entanglement-based criteria and measures become insufficient for broadband emission, e.g., from spasers (plasmonic nanolasers). We introduce criteria and measures for the (i) total entanglement of two wave packets, (ii) entanglement of a wave packet with an ensemble, and (iii) total nonclassicality of a wave packet. We discuss these criteria i...

Quantum mechanics is a highly successful yet a mysterious theory. Quantum Mechanics for Beginners provides an introduction of this fascinating subject to someone with only a high school background in physics and mathematics. This book, except the last chapter on the Schrödinger equation, is entirely algebra-based. A major strength of this book is t...

Conventional spectroscopy uses classical light to detect matter properties through the variation of its response with frequencies or time delays. Quantum light opens up new avenues for spectroscopy by utilizing parameters of the quantum state of light as novel control knobs and through the variation of photon statistics by coupling to matter. This...

We propose a scheme to control the spin Hall effect (SHE) of light reflected from a Kretschmann configuration containing an N-type coherent atomic medium. Owing to the excitation of surface plasmon resonance (SPR), enhanced spin splitting occurs in the reflection dip for TM-polarized incident light. The magnitude and sign of the transverse shifts o...

A metal-clad waveguide backed by a coherent atomic medium is proposed to achieve tunable giant spatial and angular Goos-Hänchen (GH) shifts. With a metal layer of appropriate thickness, a large GH shift can occur simultaneously for transverse-magnetic- and transverse-electric-polarized light beams when the waveguide modes are resonantly excited. Th...

We present a scheme for enhancing Goos-Hänchen shift of light beam that is reflected from a coherent atomic medium in the Kretschmann-Raether configuration. The complex permittivity of the medium can be coherently controlled and has significant influence on the surface plasmon resonance (SPR) at the metal-medium interface. By tuning the atomic abso...

Optical potentials have been a versatile tool for the study of atomic motions and many-body interactions in cold atoms. Recently, optical subwavelength single barriers were proposed to enhance the atomic interaction energy scale, which is based on nonadiabatic corrections to Born-Oppenheimer potentials. Here we present a study for creating an alter...

We introduce two independent quantifications for three-mode and four-mode entanglement. We investigate the conversion of one type of nonclassicality, i.e., single-mode nonclassicality, into another type of nonclassicality, i.e., multimode entanglement, in beam splitters. We observe parallel behavior of the two quantifications. The methods can be ge...

We propose a protocol for improving quantum entanglement based on a quantum scissor scheme [D. T. Pegg et al., Phys. Rev. Lett. 81, 1604 (1998)]. Compared to existing protocols for entanglement improvement, our scheme does not require biside operation on two-mode squeezed vacuum states. This greatly enhances the success probability as well as entan...

The nonclassical properties of quantum states are of tremendous interest due to their potential applications in future technologies. It has recently been realized that the concept of a "resource theory" is a powerful approach to quantifying and understanding nonclassicality. An important goal in this endeavor is to find resource theoretic measures...

We propose a protocol to protect the quantum states and entanglements from finite-temperature thermal noise via quantum gates. Compared to the common protocols protecting the quantum states and entanglements by using weak measurements and their reversals, no time-consuming weak measurements are needed in the present protocol and consequently, it is...

Chiral materials possess some unusual properties which make them interesting for useful applications in nanophotonics. In this work, we review the basic techniques used to achieve electromagnetically induced chirality in initially isotropic materials and mention some of their novel operations. Next, we investigate the transmission characteristics o...

Optical potentials have been a versatile tool for the study of atomic motions and many-body interactions in cold atoms. Recently, optical subwavelength single barriers were proposed to enhance the atomic interaction energy scale, which is based on non-adiabatic corrections to Born-Oppenheimer potentials. Here we present a study for creating a new l...

We show that two unknown quantum states, either pure or mixed, can be bidirectionally “teleported” counterfactually. In the process of information exchange, there is no physical particle traveling between two communicators. Unlike conventional quantum teleportation, our protocol requires neither prearranged entangled pairs nor Bell measurements. We...

A scheme to overcome diffraction limit in optical lithography via tunable plasmons is proposed. The plasmons are generated by a current-driven instability and are resonance amplified between the drain and source barriers of the transistor. A series of discrete deep subwavelength can be obtained by controlling the gate voltage. Thus, it is possible...

We study the dynamics of multiple Ξ-type atoms driven by a squeezed vacuum reservoir in a quasi-one-dimensional waveguide. We show that the atomic system's steady state is a pure state, and a complete population inversion can occur when the dipole moment of the second transition is almost perpendicular to the polarization of the incident squeezed l...

We present a theoretical study of high-efficiency four-wave mixing (FWM) sum-frequency generation beyond a pure electromagnetically induced transparency (EIT) technique in a five-level atomic system. In our FWM scheme, with the assistance of two Λ -type subsystems utilized to create EIT and Autler–Townes splitting (ATS), a synergetic mechanism of E...

We propose a quasi-counterfactual quantum swap gate for exchanging Alice’s unknown photon state and Bob’s unknown atomic state under the condition that only Alice’s photon may appear in the transmission channel between Alice and Bob, while the probability of the existence of photon in the transmission channel is controllable and can tend to zero. U...

We introduce two independent quantifications for 3-mode and 4-mode entanglement. We investigate the conversion of one type of nonclassicality, i.e. single-mode nonclassicality, into another type of nonclassicality, i.e. multi-mode entanglement, in beam-splitters. We observe parallel behavior of the two quantifications. The methods can be generalize...

Mode-entanglement based criteria and measures become insufficient for broadband emission, e.g. from spasers (plasmonic nano-lasers). We introduce criteria and measures for the (i) total entanglement of two wavepackets, (ii) entanglement of a wavepacket with an ensemble and (iii) total nonclassicality of a wavepacket~(WP). We discuss these criteria...

The spontaneous emission of a V-type three-level quantum emitter near graphene layers is investigated. With appropriate doping densities, graphene layers support transverse electric- (TE-) polarized surface plasmons. This kind of plasmon can enhance the decay rates of dipoles parallel to the layers, and subsequently, strong quantum interference pre...

When an atom is coupled to an opto-mechanical system, the evolution of the atom can be significantly modified by the mechanical phonon state. Previously, we showed that the anomalous population inversion can occur in this hybrid system. Here, we show that the quantum state (pure or mixed) of the mechanical mirror can be reconstructed with very high...

We introduce a scheme to reconstruct the quantum state of a mechanical mirror in a hybrid optomechanical system. The scheme involves sending a beam of two-level atoms to interact with a quantized cavity field which is weakly coupled to the mechanical mirror. We show that the measured data of the excited-state probability of the atoms can be used di...

We consider a two-level atom interacting with a quantized field in an optomechanical cavity and study the population inversion of the atom in this hybrid optomechanical system. Analytical solutions of the excited state population in the hybrid system are derived for various initial states of the cavity field and the mechanical mirror in the limit o...

A perfect lens constructed by dielectric and atomic gas slab system is investigated. By utilizing quantum coherence, the atomic gas shows simultaneous negative permittivity and permeability. Meanwhile, the loss can be neglected. The light emitted by one point source in the dielectric can be focused to another point in the other dielectric, which in...

We propose a method to deterministically prepare a desired quantum state in a one-dimensional (1D) continuum by a shaped photon pulse. This method is based on time reversal of the quantum emission process. We show that the desired quantum state such as a Dicke or timed Dicke state can be successfully prepared with very high fidelity even if the dis...

A deep subwavelength structured illumination microscopy scheme via tunable plasmons is proposed. The sample is placed on a semiconductor heterostructure where terahertz plasmons generated by a current-driven instability illuminate it. Full coverage of the spatial frequency regime is obtained by tuning the plasmons through adjusting gate voltage. He...

Quantum illumination takes advantage of quantum entanglement to achieve low error probability for detecting a low reflective object embedded in a noisy thermal bath. The two-mode squeezed state (TMSS), which is a Gaussian state, has been applied to quantum illumination as the detecting states in experiment. The photon-subtracted TMSS has also been...

Wolf effect refers to a spectral shift of light during its propagation even in free space, which results from the fluctuating (or correlation) nature of light sources. In conventional optics, the propagation laws of light are usually considered in flat space. However, optical phenomena are fascinating in the presence of space curvature. Here the pr...

We propose a method to deterministically prepare an arbitrary quantum state in a one-dimensional (1D) continuum by a shaped photon pulse. This method is based on time-reverse of the quantum emission process. We show that the desired quantum state such as Dicke or timed-Dicke state can be successfully prepared with very high fidelity even if the dis...

The resolution of an interferometric optical lithography system is about the half wavelength of the illumination light. We proposed a method based on Doppleron resonance to achieve a resolution beyond half wavelength [Phys. Rev. Lett. 96, 163603 (2006)]. Here, we analyze a possible experimental demonstration of this method in the negatively charged...

We propose a quantum secure group communication protocol for the purpose of sharing the same message among multiple authorized users. Our protocol can remove the need for key management that is needed for the quantum network built on quantum key distribution. Comparing with the secure quantum network based on BB84, we show our protocol is more effi...

We study the dynamics of a general multi-emitter system coupled to the squeezed vacuum reservoir and derive a master equation for this system based on the Weisskopf-Wigner approximation. In this theory, we include the effect of positions of the squeezing sources which is usually neglected in the previous studies. We apply this theory to a quasi-one...

We study the dynamics of a general multi-emitter system coupled to the squeezed vacuum reservoir and derive a master equation for this system based on the Weisskopf-Wigner approximation. In this theory, we include the effect of positions of the squeezing sources which is usually neglected in the previous studies. We apply this theory to a quasi-one...

A standard method to obtain information on a quantum state is to measure marginal distributions along many different axes in phase space, which forms a basis of quantum state tomography. We theoretically propose and experimentally demonstrate a general framework to manifest nonclassicality by observing a single marginal distribution only, which pro...

Due to the interaction with the environment, a quantum state is subjected to decoherence which becomes one of the biggest problems for practical quantum computation. Amplitude damping is one of the most important decoherence processes. Here, we show that general two-qubit mixed states undergoing an amplitude damping can be almost completely restore...

We address criticisms made in the preceding Comment by Vaidman regarding our claims of counterfactuality of transmission of a quantum state in our recent work.

The waveguide quantum electrodynamics (QED) system may have important applications in quantum device and quantum information technology. In this article we review the methods being proposed to calculate photon transport in a one-dimensional (1D) waveguide coupled to quantum emitters. We first introduce the Bethe ansatz approach and the input-output...

We present a proposal for reversing the weak (partial-collapse) quantum measurement on a cavity field with arbitrary maximum photon number. We start by putting forth a protocol to realize quantum phase gates between the cavity field and an ancilla qubit. Afterward, adopting these phase gates and some other quantum gates, we can determine the revers...

It is well known that there is a bottleneck for nonlinear all-optical switching, namely, the switching power and the switching time cannot be lowered simultaneously. A lower switching power requires a resonator with a high quality (Q) factor, but leads to a longer switching time. We propose to overcome this bottleneck by replacing the nonlinear cav...

An atomic chain coupled to a one-dimensional (1D) photonic waveguide can become a very good atom mirror. This atom mirror can have a very high reflectivity for a single-photon pulse due to the collective interaction between the atoms. Two atom arrays coupled to a 1D waveguide can form a good cavity. When a single-photon pulse is incident from one s...

Negative refraction of a probe field is studied in a dense gas consisting of cascade-type four-level atoms. By coupling the magnetic component of the probe field to a Λ scheme with initially prepared coherence in the two lower levels, strong negative permeability with minimal absorption can be obtained. The permittivity of the gas to the electric c...