Mohammad D Al-Amri

King Abdulaziz City for Science and Technology | KACST · NCQOQI

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...

We study the Goos–Hänchen shift (GHS) of a reflected light beam from a cavity containing a double-Λ\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\Lambda$$\end{documen...

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...

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...

The ability to communicate secure information is of utmost importance. Hitherto, this has been achieved within the domain of classical communication by capitalizing on mathematical complexity. However, classical communication has limitations of both speed and security. As a result, the focus has shifted towards quantum physics for the implementatio...

We design a switch based on a switchable magnetic hyperbolic metamaterial that consists of a one-dimensional periodic stacking of dielectric and gyromagnetic layers. The isofrequency curve of the structure can be switched between elliptical and hyperbolic shapes via the external DC magnetic field. The isofrequency curve relates directly to the prop...

We present how basic logic gates including nand, nor, and xor gates can be implemented counterfactually. The two inputs (Bob and Charlie) and the output (Alice) of the proposed counterfactual logic gate are not within the same station but rather separated in three different locations. We show that there is no need to prearrange entanglement for the...

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,...

Trojan horse attack is a common eavesdropping strategy which can attack various quantum secure communication systems. Its basic idea is to send auxiliary photons into a legitimate communicator's apparatuses and steal information by analyzing the reflected photons. In this paper, we consider a different kind of Trojan horse attack, the so-called cou...

We present how basic logic gates including NAND, NOR and XOR gate can be achieved counterfactually. The inputs and outputs of these counterfactual logic gates are not within the same station but rather separated at different locations. We show that there is no need to pre-arrange entanglement for the proposed counterfactual logic gates, and more im...

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...

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...

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...

Double Λ inside a Fabry-Pérot cavity is investigated. Using weak probe beam, two strong driving fields, and incoherent pumping mechanism, along with white light cavity conditions to produce three white bands in one cavity.

The Casimir force between electric and magnetic hyperbolic metamaterial slabs is investigated. Due to hyperbolic dispersion, the electromagnetic features of these metamaterials along the optical axis are different from those perpendicular to the optical axis; consequently, these features contribute differently to the Casimir effect. The repulsive C...

We theoretically investigate the double-Λ scheme inside a Fabry-Pérot cavity employing a weak probe beam and two strong driving fields together with an incoherent pumping mechanism. By generating analytical expressions for the susceptibility and applying the white-light cavity conditions, we devise a procedure that reaches the white-light condition...

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...

In the waveguide quantum electrodynamics (QED) system, emitter separation plays an important role for its functionality. Here, we present a method to measure the deep-subwavelength emitter separation in a waveguide-QED system. In this method, we can also determine the number of emitters within one di raction-limited spot. In addition, we also show...

In the waveguide quantum electrodynamics (QED) system, emitter separation plays an important role for its functionality. Here, we present a method to measure the deep-subwavelength emitter separation in a waveguide-QED system. In this method, we can also determine the number of emitters within one diffraction-limited spot. In addition, we also show...

The Goos-Hänchen (GH) shift of light beam incident on graphene ribbon array is investigated by Green’s function method. Due to the resonance effects of leaky surface plasmons on ribbons, the zeroth-order reflection field shows both giant positive and negative GH shifts. By tuning the graphene Fermi level, we can control the shift conveniently. This...

We study the thermal Casimir-Polder (CP) forces on a V-type three-level atom. The competition between the thermal effect and the quantum interference of the two transition dipoles on the force is investigated. To shed light onto the role of the quantum interference, we analyze two kinds of initial states of the atom, i.e., the superradiant state an...

In the waveguide quantum electrodynamics (QED) system, emitter separation plays an important role for its functionality. Here, we present a method to measure the deep-subwavelength emitter separation in a waveguide-QED system. In this method, we can also determine the number of emitters within one diffraction-limited spot. In addition, we also show...

Light and light based technologies have played an important role in transforming our lives via scientific contributions spanned over thousands of years. In this book we present a vast collection of articles on various aspects of light and its applications in the contemporary world at a popular or semi-popular level. These articles are written by th...

For the first time, we show how quantum teleportation can be achieved without the assistance of classical channels. Our protocol does not need any pre-established entangled photon pairs beforehand. Just by utilizing quantum Zeno effect and couterfactual communication idea, we can achieve two goals; entangling a photon and an atom and also disentang...

The dielectric cylinder covered with graphene (DCCG) is found to be a promising platform for studying multi-qubit collective effects. The plasmons supported by DCCG have huge wave numbers and low loss. Under some conditions, the zeroth- and first-order modes even have the same wavelength. Qubits along DCCG can interact with each other strongly by c...

In this paper, we investigate the counterintuitive dispersion effect associated with the poles and zeros of reflection and transmission functions in an Otto configuration when a surface plasmon resonance is excited. We show that the zeros and/or poles in the reflection and transmission functions may move into the upper-half complex-frequency plane...

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.

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...

DOI:http://dx.doi.org/10.1103/PhysRevA.93.029901

The Casimir-Polder (CP) force acting on a V-type three-level atom which is initially prepared in two different kinds of superposition states, i.e., subradiant and superradiant states, is investigated. The influence of quantum interference on force evolution due to two-dipole transitions is analyzed in detail. It is found that the orientation of the...

We show that an unknown quantum state can be transferred with neither quantum nor classical particle traveling in the transmission channel. Our protocol does not require prearranged entangled photon pairs and Bell measurements. By utilizing quantum Zeno effect and counterfactuality, we can entangle and disentangle a photon and an atom by nonlocal i...

In traditional Hanbury Brown–Twiss (HBT) schemes, thermal intensity-intensity correlations (IICs) are phase insensitive. Here we propose a modified HBT scheme with phase conjugation to demonstrate phase-sensitive and nonfactorizable features of thermal IIC speckles. It shows that the novel phase-sensitive features originate from the correlation bet...

We investigate, within the weak measurement theory, the advantages of non-classical pointer states over semi-classical ones for coherent, squeezed vacuum, and Schr\"odinger cat states. These states are utilized as pointer state for the system operator \hat{A}with property \hat{A}^{2}=\hat{I} , where \hat{I} represents the identity operator. We calc...

We propose a scheme for microscopy with resolution far beyond the diffraction limit by using coherent Rabi oscillations. When the sample is illuminated by a gradient laser field, Rabi oscillations will be induced which can lead to a sinusoidal excitation in the sample. This is similar to the structured illumination microscopy (SIM) which can recove...

The resolution of a photolithography and optical imaging system is restricted by the diffraction limit. Coherent Rabi oscillations have been shown to be able to overcome the diffraction limit in a simple two-level atomic system (Z Liao, M Al-amri, and M S Zubairy 2010 Phys. Rev. Lett. 105 183601). In this paper, we numerically calculate the wave p...

Preservation of quantum entanglement in a two-qubit system is achieved by use of the disclosed systems. Three different example two-qubit systems are shown: (1) a system employing a weak measurement, (2) a system in which a generalized amplitude dampening occurs without use of a weak measurement, and (3) an extended system in which the system is pr...

A Reply to the Comment by Baranov et al.

Using graphene plasmons (GPs), we can realize a nanometer-scale microscopy. Our scheme takes advantage of the extremely large wave number of GPs and the low loss of graphene. Comparing with conventional nonlinear structured-illumination microscopy based on high-order nonlinearity associated with high intensity light, our proposal only requires line...

It has long been assumed in physics that for information to travel in empty space between two parties (the Sender and the Receiver), “physically real” entities have to travel between the parties. The recently discovered technique of interaction-free measurement—wherein the presence of an object is inferred without the object directly interacting wi...

In traditional Hanbury Brown and Twiss (HBT) schemes, the thermal intensity-intensity correlations are phase insensitive. Here we propose a modified HBT scheme with phase conjugation to demonstrate the phase-sensitive and nonfactorizable features for thermal intensity-intensity correlation speckle. Our scheme leads to results that are similar to th...

A quantum-degenerate Fermi gas in an optical cavity is investigated. It is shown that there exists a self-organization phase transition. This phase transition can be identified as the Dicke quantum phase transition. This investigation opens the door to include degenerate Fermi gases in the group of atomic systems which exhibit a self-organization t...

We demonstrate the counterintuitive dispersion effect that the peaks (dips) in the gain spectrum correspond to abnormal (normal) dispersion, contrary to the usual Kramers-Kronig point of view. This effect may also lead to two unique features: a broadband abnormal dispersion region and an observable Hartman effect. These results are explained in ter...

We propose a protocol for direct quantum communication between two parties (Alice and Bob) which is achieved by controlling the phase of the signal photon. Without imperfection and noise, Alice's two detectors always click with unit probability according to Bob's different decisions. The probability of detecting a photon in the transmission channel...

DOI:https://doi.org/10.1103/PhysRevLett.112.208902

We study the Casimir-Polder (CP) force on an excited cold two-level atom in structures containing metamaterials. We adopt two kinds of metamaterials: left-handed materials (LHMs) and zero-index materials (ZIMs). The CP force on an excited atom can be divided into two parts: the dispersive force that responds to all frequencies of the electromagneti...

In reply to Vaidman's Comment [arXiv:1304.6689], we show that his claim that our Protocol for Direct Counterfactual Quantum Communication [PRL 110, 170502 (2013), arXiv:1206.2042] is counterfactual only for one type of information bit is wrong.

The resolution of optical lithography and the spacing of atom lithography are limited by about half of the wavelength due to the Rayleigh limit. Here we propose a coherent atom lithography experiment which can print nanometer structures. In this proposal, we show that subwavelength spatial distribution of the atoms in the excited state can be achie...

A sub-wavelength photolithographic method includes exposing a photoresist material to a stimulating electromagnetic source prior to further exposing the photoresist material to a dissociating electromagnetic source. The stimulating electromagnetic source induces Rabi oscillations in the photoresist material between a first molecular state and an ex...

We propose a scheme for the entanglement generation of two micromechanical mirrors through two-mode fields generated by a correlated emission laser source in a doubly resonant cavity. The coherence between upper and lower levels is generated in a cascade-driven scheme using two external classical fields. Two input laser fields are both tuned at the...

We present an analysis of a nested Mach-Zehnder interferometer in which an ensemble of identical pre- and postselected particles leaves a weak trace. A knowledge of the weak value partially destroys the quantum interference. The results, contrary to some recent claims [Vaidman, Phys. Rev. A 87, 052104 (2013)], are in accordance with the usual quant...

Using a technique, analogous to coherent population trapping in an atomic system, we propose schemes to create transverse light propagation violating left-right symmetry in a photonic circuit consisting of three coupled waveguides. The frequency windows for the symmetry breaking of the left-right energy flow span over 80 nm. Our proposed system onl...

A sub-wavelength photolithographic method includes exposing a photoresist material to a stimulating electromagnetic source prior to further exposing the photoresist material to a dissociating electromagnetic source. The stimulating electromagnetic source induces Rabi oscillations in the photoresist material between a first molecular state and an ex...

The resolutions of the optical lithography is limited by the well-known Rayleigh limit. Although the atom lithography can generate features smaller than this limit, the spacing of the pattern is still limited by the optical wavelength. Here, we proposed two atom lithography methods, both of which used the coherent Rabi oscillation to break the diff...

We propose an experimental scheme for entangling two macroscopic mechanical resonators (movable mirrors) by their coupling to the two-mode fields of a correlated-emission laser inside a doubly resonant cavity. With this aim we investigate the quantum Langevin equations that describe the interaction of the field-mirror system in conjuction with the...

Quantum entanglement is a critical resource for quantum information and quantum computation. However, entanglement of a quantum system is subjected to change due to the interaction with the environment. One typical result of the interaction is the amplitude damping that usually results in the reduction of the entanglement. Here we propose a protoco...

We present an analysis of a double Mach-Zehnder interferometer in which an ensemble of identical pre- and postselected particles leave a weak trace. A knowledge of the weak value partially destroys the quantum interference. The results, contrary to some recent claims, are in accordance with the usual quantum mechanical expectations.

It has long been assumed in physics that for information to travel between two parties in empty space, "Alice" and "Bob," physical particles have to travel between them. Here, using the "chained" quantum Zeno effect, we show how, in the ideal asymptotic limit, information can be transferred between Alice and Bob without any physical particles trave...

The nonlinear dynamics of the photon number in an optical cavity filled with a cigar-shaped Bose-Einstein condensate is investigated. We find that the way of adding the field is crucial to the switching close to the critical transition point. If the pump field is changed abruptly, the system may jump from one branch to the other even if the pump fi...

The spontaneous emission of a two-level atom in a anisotropic photonic crystal is investigated without making use of the rotating wave approximation (RWA). Similar to the RWA case, there exist two characteristic atomic transition frequencies which separate the radiation field from the localized and propagated fields. Unlike the RWA calculation, the...

Controlling reflectivity optically over a wide range of frequency band can be of great demand technologically. In this paper we show how this can be realized using a Fabry-P´erot cavity filled with a three-level atomic gas. Furthermore, we employ both concepts of electromagnetic induced transparency EIT and the white light cavity which in turn play...

We propose two atom lithography techniques with subwavelength resolution based on position-dependent Rabi oscillations. Our method either uses neutral or ionized atoms to write subwavelength patterns. We illustrate our proposal by numerical simulations of an experimental setup using rubidium Rydberg atoms. We show that, for a microwave wavelength o...

Methods and systems are disclosed for restoring a state of a qubit transformed by a weak measurement to its original state. Unlike traditional methods, in which, the restoration was carried out by way of another weak measurement, the disclosed method uses an additional qubit, referred to as the ancillary qubit, and appropriate Hadamard and CNOT tra...

Controlling reflectivity optically over a wide range of frequency band can be of great demand. We show how such a devise can be realized using a Fabry-Perot cavity filled with a three-level atomic gas.

We consider a three-level atomic medium and discuss how to control the Goos-Hänchen and Imbert-Fedorov shifts for a circular polarized Gaussian beam via pump and coherent driving field applied to the atomic medium. The susceptibility of the atomic medium can be adjusted by changing the driving field and pump. Consequently, for a fixed driving field...

In classical optical lithography, resolution is limited to about half of the wavelength of the source used in the process. However, as we reach high frequencies (Deep UV or X-ray), several problems and difficulties occur. Over the last decade, several techniques were suggested to go beyond the classical limit. In 2010, Liao, Alamri, and Zubairy pro...

The resolutions of the optical microscope and the optical lithography are both limited by the well-known Rayleigh limit. Rabi oscillation is a coherent nonlinear process that can modulate the population distribution between two energy states and also modulate the resonant fluorescence spectrum. If we have a gradient electric field amplitude in the...

We propose a device whose reflectivity can be controlled optically over a wide frequency band. To this objective, we propose a Fabry-Pérot cavity filled with a three-level atomic gas such that the effective susceptibility can be adjusted through incoherent pump and coherent driving fields. Adopting the concepts of electromagnetic-induced transparen...

It is well-known that traditional optical lithography is restricted by the Rayleigh limit such that the smallest feature that can be generated is restricted to half the wavelength of the light source. Thus light beams with shorter and shorter wavelength have been applied to print smaller and smaller circuit images. However, when it comes to the ext...

We propose a scheme for the quantum teleportation of an arbitrary 2N-dimensional macroscopic atomic ensemble state. The state to be teleported is encoded in N ensembles of atoms subsequently interacting with a cavity at the sender side and there are equivalent atomic ensembles at the receiver side. Our scheme relies on the transformation of atomic...

We present a scheme for subwavelength single-atom localization that is based on the photon statistics measurement of the resonance fluorescence from the two-level atomic system. The photon number distribution of the resonance fluorescence depends on the position of the atom inside the standing-wave driving field via the position-dependent Rabi freq...

We evaluate the resonance-fluorescence spectrum of a bunch of two-level atoms driven by a gradient coherent laser field. The result shows that we can determine the positions of atoms from the spectrum even when the atoms locate within the subwavelength range and the dipole-dipole interaction is significant. This far-field resonance-fluorescence-loc...

We discuss the coupling of two identical atoms, separated by a metal or metamaterial slab, through surface modes. We show that the coupling through the surface modes can induce entanglement. We discuss how to control the coupling for the metal or metamaterial slab by adjusting the symmetrical and antisymmetrical property of the surface modes. We an...

We propose a protocol for the reversal of a weak measurement on a qubit and discuss a possible experimental scheme for the state protection in a cavity QED system. Unlike previous methods for the reversal of weak measurement, the proposed scheme does not require another weak measurement in the reversal process and therefore can be accomplished in a...

We present a procedure for subwavelength optical microscopy. The identical atoms are distributed on a plane and shined with a standing wave. We rotate the plane to different angles and record the resonant fluorescence spectra in the far field, from which we can obtain their distance and location information. This procedure also works for atomic sep...

The optical bistability of an ultracold atomic ensemble located in a small-volume ultrahigh-finesse optical cavity is investigated. We find that a transverse pumping field can be used to control the bistable behavior of the intracavity photons induced by the input pumping along the cavity axis. This phenomenon can be used as a controllable optical...

A subwavelength localization scheme of a single atom is investigated. The localization is based on the interaction of the two-level atom with a standing wave laser field. The photon statistics of resonant fluorescence depends on the Rabi frequency of the driving laser field and thus the position of the atom inside the standing wave. We show that th...