Zbigniew Ficek - Profile on Academia.edu (original) (raw)

Papers by Zbigniew Ficek

Quantum interference effects in a cavity QED system

Journal of optics, Jun 16, 2003

ABSTRACT We consider the effect of quantum interference on population distribution and photon sta... more ABSTRACT We consider the effect of quantum interference on population distribution and photon statistics of a cavity field interacting with dressed states of a strongly driven three-level atom. We analyse three coupling configurations of the cavity field to the driven atom, with the cavity frequency tuned to the outer Rabi sideband, the inner Rabi sideband and the central frequency of the 'singly dressed' three-level atom. The quantum doubly dressed states for each configuration are identified and the population distribution and photon statistics are interpreted in terms of transitions among these dressed states and their populations. We find that the population distribution depends strongly on quantum interference and the cavity damping. For the cavity field tuned to the outer or inner Rabi sidebands the cavity damping induces transitions between the dressed states which are forbidden for the ordinary spontaneous emission. Moreover, we find that in the case of the cavity field coupled to the inner Rabi sideband the population distribution is almost Poissonian with a large average number of photons that can be controlled by quantum interference. This system can be considered as a one-atom dressed-state laser with controlled intensity.

Effect of a broadband squeezed vacuum on two-atom spontaneous emission

Optics Communications, Apr 1, 1991

ABSTRACT

Atoms in squeezed light fields

Journal of Modern Optics, Mar 1, 1999

Squeezed light is of interest as an example of a non-classical state of the electromagnetic field... more Squeezed light is of interest as an example of a non-classical state of the electromagnetic field and because of its applications both in technology and in fundamental quantum physics. This review concentrates on one aspect of squeezed light, namely its application in atomic spectroscopy. The general properties, detection and application of squeezed light are first reviewed. The basic features of

Quantum interference and coherence: Theory and experiments

Springer eBooks, 2005

... from Two Nonidentical Atoms 126 3.5.4 Experimental Observation of Quantum Beats in a Type I S... more ... from Two Nonidentical Atoms 126 3.5.4 Experimental Observation of Quantum Beats in a Type I System 129 3.5.5 Quantum Beats in the Intensity—Intensity Correlations 131 3.6 Interference Pattern with a Dark Center 135 4 Quantum Interference as a Control of Decoherence ...

Journal of The Optical Society of America B-optical Physics, Nov 1, 1997

The time evolution of the populations of the collective states of a two-atom system in a squeezed... more The time evolution of the populations of the collective states of a two-atom system in a squeezed vacuum can exhibit quantum beats. We show that the effect appears only when the carrier frequency of the squeezed field is detuned from the atomic resonance. Moreover, we find that the quantum beats are not present for the case in which the two-photon correlation strength is the maximum possible for a field with a classical analog. We also show that the population inversion between the excited collective states, found for the resonant squeezed vacuum, is sensitive to the detuning and the two-photon correlations. For large detunings or a field with a classical analog there is no inversion between the collective states. Observation of the quantum beats or the population inversion would confirm the essentially quantum-mechanical nature of the squeezed vacuum.

Analytical solution for the Mollow and Autler-Townes probe absorption spectra of a three-level atom in a squeezed vacuum

Physical Review A, May 1, 1998

Saturation of a two-level atom in polychromatic fields

Journal of optics, Nov 30, 2000

ABSTRACT

arXiv (Cornell University), Oct 9, 2010

We apply the continuous variable approach to study entangled dynamics of coupled harmonic oscilla... more We apply the continuous variable approach to study entangled dynamics of coupled harmonic oscillators interacting with a thermal reservoir and to a deterministic creation of entanglement in an atomic ensemble located inside a high-Q ring cavity. In the case of harmonic oscillators, we show that a suitable unitary transformation of the position and momentum operators transforms the system to a set of independent harmonic oscillators with only one of them coupled to the reservoir. Working in the Wigner representation of the density operator, we find that the covariance matrix has a block diagonal form of smaller size matrices. This simple property allows to treat the problem to some extend analytically. We analyze the time evolution of an initial entanglement and find that the entanglement can persists for long times due to presence of constants of motion for the covariance matrix elements. In the case of an atomic ensemble located inside the cavity, the attention is focused on creation of one and two-mode continuous variable entangled states from the vacuum by applying laser pulses of a suitably adjusted amplitudes and phases. The pulses together with the cavity dissipation prepare the collective modes of the atomic ensemble in a desired entangled state.

Journal of Physics B, Oct 21, 2010

We consider an entangled but non-interacting qubit pair a 1 and b 1 that are independently couple... more We consider an entangled but non-interacting qubit pair a 1 and b 1 that are independently coupled to a set of local qubit systems, a I and b J , of 0-bit value, respectively. We derive rules for the transfer of entanglement from the pair a 1 − b 1 to an arbitrary pair a I − b J , for the case of qubit-number conserving local interactions. It is shown that the transfer rule depends strongly on the initial entangled state. If the initial entanglement is in the form of the Bell state corresponding to anti-correlated qubits, the sum of the square of the non-local pairwise concurrences is conserved. If the initial state is the Bell state with correlated qubits, this sum can be reduced, even to zero in some cases, to reveal a complete and abrupt loss of all non-local pairwise entanglement. We also identify that for the nonlocal bipartitions A − b J involving all qubits at one location, with one qubit b J at the other location, the concurrences satisfies a simple addition rule for both cases of the Bell states, that the sum of the square of the nonlocal concurrences is conserved.

Physical Review A, Mar 29, 2012

The steady-state cooling of a nanomechanical resonator interacting with three coupled quantum dot... more The steady-state cooling of a nanomechanical resonator interacting with three coupled quantum dots is studied. General conditions for the cooling to the ground state with single and two-electron dark states are obtained. The results show that in the case of the interaction of the resonator with a single-electron dark state, no cooling of the resonator occurs unless the quantum dots are not identical. The steady-state cooling is possible only if the energy state of the quantum dot coupled to the drain electrode is detuned from the energy states of the dots coupled to the electron source electrode. The detuning has the effect of unequal shifting of the effective dressed states of the system that the cooling and heating processes occur at different frequencies. For the case of two electrons injected to the quantum dot system, the creation of a two-particle dark state is established to be possible with spin-antiparallel electrons. The results predict that with the two-particle dark state, an effective cooling can be achieved even with identical quantum dots subject of an asymmetry only in the charging potential energies coupling the injected electrons. It is found that similar to the case of the single-electron dark state, the asymmetries result in the cooling and heating processes to occur at different frequencies. However, an important difference between the single and two-particle dark state cases is that the cooling process occurs at significantly different frequencies. This indicates that the frequency at which the resonator could be cooled to its ground state can be changed by switching from the one-electron to the two-electron Coulomb blockade process.

New Journal of Physics, Dec 22, 2017

The theory of phase control of coherence, entanglement and quantum steering is developed for an o... more The theory of phase control of coherence, entanglement and quantum steering is developed for an optomechanical system composed of a single mode cavity containing a partially transmitting dielectric membrane and driven by short laser pulses. The membrane divides the cavity into two mutually coupled optomechanical cavities resulting in an effective three-mode closed loop system, two field modes of the two cavities and a mechanical mode representing the oscillating membrane. The closed loop in the coupling creates interfering channels which depend on the relative phase of the coupling strengths of the field modes to the mechanical mode. Populations and correlations of the output modes are calculated analytically and show several interesting phase dependent effects such as reversible population transfer from one field mode to the other, creation of collective modes, and induced coherence without induced emission. We find that these effects result from perfect mutual coherence between the field modes which is preserved even if one of the modes is not populated. The inseparability criterion for the output modes is also investigated and we find that entanglement may occur only between the field modes and the mechanical mode. We show that depending on the phase, the field modes can act on the mechanical mode collectively or individually resulting, respectively, in tripartite or bipartite entanglement. In addition, we examine the phase sensitivity of quantum steering of the mechanical mode by the field modes. Deterministic phase transfer of the steering from bipartite to collective is predicted and optimum steering corresponding to perfect EPR state can be achieved. These different types of quantum steering can be distinguished experimentally by measuring the coincidence rate between two detectors adjusted to collect photons of the output cavity modes. In particular, we find that the minima of the interference pattern of the coincidence rate signal the bipartite steering, while the maxima signal the collective steering.

Physical Review A, Feb 20, 2014

We study multi-partite entanglement, the generation of EPR states and quantum steering in a three... more We study multi-partite entanglement, the generation of EPR states and quantum steering in a three-mode optomechanical system composed of an atomic ensemble located inside a single-mode cavity with a movable mirror. The cavity mode is driven by a short laser pulse, has a nonlinear parametric-type interaction with the mirror and a linear beamsplitter-type interaction with the atomic ensemble. There is no direct interaction of the mirror with the atomic ensemble. A threshold effect for the dynamics of the system is found, above which the system works as an amplifier and below which as an attenuator of the output fields. The threshold is determined by the ratio of the coupling strengths of the cavity mode to the mirror and to the atomic ensemble. It is shown that above the threshold the system effectively behaves as a two-mode system in which a perfect bipartite EPR state can be generated, while it is impossible below the threshold. Furthermore, a fully inseparable tripartite entanglement and even further a genuine tripartite entanglement can be produced above and below the threshold. In addition, we consider quantum steering and examine the monogamy relations that quantify the amount of bipartite steering that can be shared between different modes. It is found that the mirror is more capable for steering of entanglement than the cavity mode. The two way steering is found between the mirror and the atomic ensemble despite the fact that they are not directly coupled to each other, while it is impossible between the output of cavity mode and the ensemble which are directly coupled to each other.

Entanglement Evolution Between Two Isolated Multiqubit Systems

OSA Workshop on Entanglement and Quantum Decoherence

We examine the time evolution of entanglement between two qubits of a system of four qubits. The ... more We examine the time evolution of entanglement between two qubits of a system of four qubits. The system is composed of two separate cavities each containing a single two-level atom. The qubits of the system are the two atoms and the two cavity modes. We show that during the transfer of an initial entanglement from atoms to the cavity modes, an additional entanglement is induced between the atoms and the cavity modes. Thus, during the evolution, the system effectively behaves as a six qubit system. In addition, we study the entanglement evolution for an imperfect matching of the atoms to the cavity modes. We show that the imperfect matching can force a stable entangled state to evolve in time and may produce a continuous entanglement in time.

arXiv (Cornell University), Jul 27, 2022

Einstein-Rosen-Podolsky (EPR) steering or quantum steering describes the "spooky-action-at-adista... more Einstein-Rosen-Podolsky (EPR) steering or quantum steering describes the "spooky-action-at-adistance" that one party is able to remotely alter the states of the other if they share a certain entangled state. Generally, it admits an operational interpretation as the task of verifying entanglement without trust in the steering party's devices, making it lying intermediate between Bell nonlocality and entanglement. Together with the asymmetrical nature, quantum steering has attracted a considerable interest from theoretical and experimental sides over past decades. In this Perspective, we present a brief overview of the EPR steering with emphasis on recent progress, discuss current challenges, opportunities and propose various future directions. We look to the future which directs research to a larger-scale level beyond massless and microscopic systems to reveal steering of higher dimensionality, and to build up steered networks composed of multiple parties.

Quantum Harmonic Oscillator

Problems and Solutions in Quantum Physics, 2016

Relativistic Schrödinger Equation

Quantum Physics for Beginners, 2017

Planck’s Quantum Hypothesis: Birth of Quantum Theory

Problems and Solutions in Quantum Physics, 2016

Applications of Schrödinger Equation: Potential (Quantum) Wells

Problems and Solutions in Quantum Physics, 2016

Interaction between two quantized cavity modes via an ensemble of four-level atoms in the diamond configuration

arXiv: Quantum Physics, 2016

We study a four-level atom in the diamond configuration interacting with two quantized field mode... more We study a four-level atom in the diamond configuration interacting with two quantized field modes supported by a cavity. We show that such Diamond\DiamondDiamond-type atoms intermediate in the interaction between these two modes of the cavity only if lasers drive both transitions to the highest energy level. This system offers thus a fully controllable effective coupling between the two modes. Moreover, we present two applications of this system: a scheme that maps a quantum state of one mode onto the second mode on demand and a fast opening high-Q cavity system that can be easily and coherently controlled with laser fields. Finally, we investigate the feasibility of the fast opening high-Q cavity system and show that this scheme can be implemented experimentally.

Quantum interference effects in a cavity QED system

Journal of optics, Jun 16, 2003

ABSTRACT We consider the effect of quantum interference on population distribution and photon sta... more ABSTRACT We consider the effect of quantum interference on population distribution and photon statistics of a cavity field interacting with dressed states of a strongly driven three-level atom. We analyse three coupling configurations of the cavity field to the driven atom, with the cavity frequency tuned to the outer Rabi sideband, the inner Rabi sideband and the central frequency of the 'singly dressed' three-level atom. The quantum doubly dressed states for each configuration are identified and the population distribution and photon statistics are interpreted in terms of transitions among these dressed states and their populations. We find that the population distribution depends strongly on quantum interference and the cavity damping. For the cavity field tuned to the outer or inner Rabi sidebands the cavity damping induces transitions between the dressed states which are forbidden for the ordinary spontaneous emission. Moreover, we find that in the case of the cavity field coupled to the inner Rabi sideband the population distribution is almost Poissonian with a large average number of photons that can be controlled by quantum interference. This system can be considered as a one-atom dressed-state laser with controlled intensity.

Effect of a broadband squeezed vacuum on two-atom spontaneous emission

Optics Communications, Apr 1, 1991

ABSTRACT

Atoms in squeezed light fields

Journal of Modern Optics, Mar 1, 1999

Squeezed light is of interest as an example of a non-classical state of the electromagnetic field... more Squeezed light is of interest as an example of a non-classical state of the electromagnetic field and because of its applications both in technology and in fundamental quantum physics. This review concentrates on one aspect of squeezed light, namely its application in atomic spectroscopy. The general properties, detection and application of squeezed light are first reviewed. The basic features of

Quantum interference and coherence: Theory and experiments

Springer eBooks, 2005

... from Two Nonidentical Atoms 126 3.5.4 Experimental Observation of Quantum Beats in a Type I S... more ... from Two Nonidentical Atoms 126 3.5.4 Experimental Observation of Quantum Beats in a Type I System 129 3.5.5 Quantum Beats in the Intensity—Intensity Correlations 131 3.6 Interference Pattern with a Dark Center 135 4 Quantum Interference as a Control of Decoherence ...

Journal of The Optical Society of America B-optical Physics, Nov 1, 1997

The time evolution of the populations of the collective states of a two-atom system in a squeezed... more The time evolution of the populations of the collective states of a two-atom system in a squeezed vacuum can exhibit quantum beats. We show that the effect appears only when the carrier frequency of the squeezed field is detuned from the atomic resonance. Moreover, we find that the quantum beats are not present for the case in which the two-photon correlation strength is the maximum possible for a field with a classical analog. We also show that the population inversion between the excited collective states, found for the resonant squeezed vacuum, is sensitive to the detuning and the two-photon correlations. For large detunings or a field with a classical analog there is no inversion between the collective states. Observation of the quantum beats or the population inversion would confirm the essentially quantum-mechanical nature of the squeezed vacuum.

Analytical solution for the Mollow and Autler-Townes probe absorption spectra of a three-level atom in a squeezed vacuum

Physical Review A, May 1, 1998

Saturation of a two-level atom in polychromatic fields

Journal of optics, Nov 30, 2000

ABSTRACT

arXiv (Cornell University), Oct 9, 2010

We apply the continuous variable approach to study entangled dynamics of coupled harmonic oscilla... more We apply the continuous variable approach to study entangled dynamics of coupled harmonic oscillators interacting with a thermal reservoir and to a deterministic creation of entanglement in an atomic ensemble located inside a high-Q ring cavity. In the case of harmonic oscillators, we show that a suitable unitary transformation of the position and momentum operators transforms the system to a set of independent harmonic oscillators with only one of them coupled to the reservoir. Working in the Wigner representation of the density operator, we find that the covariance matrix has a block diagonal form of smaller size matrices. This simple property allows to treat the problem to some extend analytically. We analyze the time evolution of an initial entanglement and find that the entanglement can persists for long times due to presence of constants of motion for the covariance matrix elements. In the case of an atomic ensemble located inside the cavity, the attention is focused on creation of one and two-mode continuous variable entangled states from the vacuum by applying laser pulses of a suitably adjusted amplitudes and phases. The pulses together with the cavity dissipation prepare the collective modes of the atomic ensemble in a desired entangled state.

Journal of Physics B, Oct 21, 2010

We consider an entangled but non-interacting qubit pair a 1 and b 1 that are independently couple... more We consider an entangled but non-interacting qubit pair a 1 and b 1 that are independently coupled to a set of local qubit systems, a I and b J , of 0-bit value, respectively. We derive rules for the transfer of entanglement from the pair a 1 − b 1 to an arbitrary pair a I − b J , for the case of qubit-number conserving local interactions. It is shown that the transfer rule depends strongly on the initial entangled state. If the initial entanglement is in the form of the Bell state corresponding to anti-correlated qubits, the sum of the square of the non-local pairwise concurrences is conserved. If the initial state is the Bell state with correlated qubits, this sum can be reduced, even to zero in some cases, to reveal a complete and abrupt loss of all non-local pairwise entanglement. We also identify that for the nonlocal bipartitions A − b J involving all qubits at one location, with one qubit b J at the other location, the concurrences satisfies a simple addition rule for both cases of the Bell states, that the sum of the square of the nonlocal concurrences is conserved.

Physical Review A, Mar 29, 2012

The steady-state cooling of a nanomechanical resonator interacting with three coupled quantum dot... more The steady-state cooling of a nanomechanical resonator interacting with three coupled quantum dots is studied. General conditions for the cooling to the ground state with single and two-electron dark states are obtained. The results show that in the case of the interaction of the resonator with a single-electron dark state, no cooling of the resonator occurs unless the quantum dots are not identical. The steady-state cooling is possible only if the energy state of the quantum dot coupled to the drain electrode is detuned from the energy states of the dots coupled to the electron source electrode. The detuning has the effect of unequal shifting of the effective dressed states of the system that the cooling and heating processes occur at different frequencies. For the case of two electrons injected to the quantum dot system, the creation of a two-particle dark state is established to be possible with spin-antiparallel electrons. The results predict that with the two-particle dark state, an effective cooling can be achieved even with identical quantum dots subject of an asymmetry only in the charging potential energies coupling the injected electrons. It is found that similar to the case of the single-electron dark state, the asymmetries result in the cooling and heating processes to occur at different frequencies. However, an important difference between the single and two-particle dark state cases is that the cooling process occurs at significantly different frequencies. This indicates that the frequency at which the resonator could be cooled to its ground state can be changed by switching from the one-electron to the two-electron Coulomb blockade process.

New Journal of Physics, Dec 22, 2017

The theory of phase control of coherence, entanglement and quantum steering is developed for an o... more The theory of phase control of coherence, entanglement and quantum steering is developed for an optomechanical system composed of a single mode cavity containing a partially transmitting dielectric membrane and driven by short laser pulses. The membrane divides the cavity into two mutually coupled optomechanical cavities resulting in an effective three-mode closed loop system, two field modes of the two cavities and a mechanical mode representing the oscillating membrane. The closed loop in the coupling creates interfering channels which depend on the relative phase of the coupling strengths of the field modes to the mechanical mode. Populations and correlations of the output modes are calculated analytically and show several interesting phase dependent effects such as reversible population transfer from one field mode to the other, creation of collective modes, and induced coherence without induced emission. We find that these effects result from perfect mutual coherence between the field modes which is preserved even if one of the modes is not populated. The inseparability criterion for the output modes is also investigated and we find that entanglement may occur only between the field modes and the mechanical mode. We show that depending on the phase, the field modes can act on the mechanical mode collectively or individually resulting, respectively, in tripartite or bipartite entanglement. In addition, we examine the phase sensitivity of quantum steering of the mechanical mode by the field modes. Deterministic phase transfer of the steering from bipartite to collective is predicted and optimum steering corresponding to perfect EPR state can be achieved. These different types of quantum steering can be distinguished experimentally by measuring the coincidence rate between two detectors adjusted to collect photons of the output cavity modes. In particular, we find that the minima of the interference pattern of the coincidence rate signal the bipartite steering, while the maxima signal the collective steering.

Physical Review A, Feb 20, 2014

We study multi-partite entanglement, the generation of EPR states and quantum steering in a three... more We study multi-partite entanglement, the generation of EPR states and quantum steering in a three-mode optomechanical system composed of an atomic ensemble located inside a single-mode cavity with a movable mirror. The cavity mode is driven by a short laser pulse, has a nonlinear parametric-type interaction with the mirror and a linear beamsplitter-type interaction with the atomic ensemble. There is no direct interaction of the mirror with the atomic ensemble. A threshold effect for the dynamics of the system is found, above which the system works as an amplifier and below which as an attenuator of the output fields. The threshold is determined by the ratio of the coupling strengths of the cavity mode to the mirror and to the atomic ensemble. It is shown that above the threshold the system effectively behaves as a two-mode system in which a perfect bipartite EPR state can be generated, while it is impossible below the threshold. Furthermore, a fully inseparable tripartite entanglement and even further a genuine tripartite entanglement can be produced above and below the threshold. In addition, we consider quantum steering and examine the monogamy relations that quantify the amount of bipartite steering that can be shared between different modes. It is found that the mirror is more capable for steering of entanglement than the cavity mode. The two way steering is found between the mirror and the atomic ensemble despite the fact that they are not directly coupled to each other, while it is impossible between the output of cavity mode and the ensemble which are directly coupled to each other.

Entanglement Evolution Between Two Isolated Multiqubit Systems

OSA Workshop on Entanglement and Quantum Decoherence

We examine the time evolution of entanglement between two qubits of a system of four qubits. The ... more We examine the time evolution of entanglement between two qubits of a system of four qubits. The system is composed of two separate cavities each containing a single two-level atom. The qubits of the system are the two atoms and the two cavity modes. We show that during the transfer of an initial entanglement from atoms to the cavity modes, an additional entanglement is induced between the atoms and the cavity modes. Thus, during the evolution, the system effectively behaves as a six qubit system. In addition, we study the entanglement evolution for an imperfect matching of the atoms to the cavity modes. We show that the imperfect matching can force a stable entangled state to evolve in time and may produce a continuous entanglement in time.

arXiv (Cornell University), Jul 27, 2022

Einstein-Rosen-Podolsky (EPR) steering or quantum steering describes the "spooky-action-at-adista... more Einstein-Rosen-Podolsky (EPR) steering or quantum steering describes the "spooky-action-at-adistance" that one party is able to remotely alter the states of the other if they share a certain entangled state. Generally, it admits an operational interpretation as the task of verifying entanglement without trust in the steering party's devices, making it lying intermediate between Bell nonlocality and entanglement. Together with the asymmetrical nature, quantum steering has attracted a considerable interest from theoretical and experimental sides over past decades. In this Perspective, we present a brief overview of the EPR steering with emphasis on recent progress, discuss current challenges, opportunities and propose various future directions. We look to the future which directs research to a larger-scale level beyond massless and microscopic systems to reveal steering of higher dimensionality, and to build up steered networks composed of multiple parties.

Quantum Harmonic Oscillator

Problems and Solutions in Quantum Physics, 2016

Relativistic Schrödinger Equation

Quantum Physics for Beginners, 2017

Planck’s Quantum Hypothesis: Birth of Quantum Theory

Problems and Solutions in Quantum Physics, 2016

Applications of Schrödinger Equation: Potential (Quantum) Wells

Problems and Solutions in Quantum Physics, 2016

Interaction between two quantized cavity modes via an ensemble of four-level atoms in the diamond configuration

arXiv: Quantum Physics, 2016

We study a four-level atom in the diamond configuration interacting with two quantized field mode... more We study a four-level atom in the diamond configuration interacting with two quantized field modes supported by a cavity. We show that such Diamond\DiamondDiamond-type atoms intermediate in the interaction between these two modes of the cavity only if lasers drive both transitions to the highest energy level. This system offers thus a fully controllable effective coupling between the two modes. Moreover, we present two applications of this system: a scheme that maps a quantum state of one mode onto the second mode on demand and a fast opening high-Q cavity system that can be easily and coherently controlled with laser fields. Finally, we investigate the feasibility of the fast opening high-Q cavity system and show that this scheme can be implemented experimentally.