Manzoor Ikram - Academia.edu (original) (raw)
Papers by Manzoor Ikram
Journal of Physics B-atomic Molecular and Optical Physics, 2007
We propose a scheme for generation of highly non-classical entangled field states of the type \fr... more We propose a scheme for generation of highly non-classical entangled field states of the type \frac{1}{\sqrt{2}}(|n,0\rangle \pm |0,n\rangle ) in the cavity QED scenario. The scheme utilizes an atomic analogue of the Mach Zehnder interferometer having a quantized field in the high-Q cavity containing a superposition of zero and one photon that acts as the first beam splitter. The probability for production of the desired states may approach a value close to unity with high fidelity under prevailing experimental conditions.
Journal of Physics B-atomic Molecular and Optical Physics, 2012
We investigate the entanglement dynamics of a bipartite atomic system, with atoms being close tog... more We investigate the entanglement dynamics of a bipartite atomic system, with atoms being close together, interacting with a common vacuum reservoir. We show that local unitary operations such as Pauli-x and Pauli-z on single or both atoms can lead to a significant positive change in the subsequent evolution of the entanglement. Sudden death of the entanglement can be delayed and
Physical Review A, 2004
We propose a scheme for the measurement of joint photon statistics and Wigner function of the ent... more We propose a scheme for the measurement of joint photon statistics and Wigner function of the entangled field states between two separate cavities. The scheme utilizes the momentum state of the two-level atoms in Bragg's regime. The probability of finding the atom in any one of the momentum states is the product of joint photon statistics and an oscillatory function.
Journal of Physics B-atomic Molecular and Optical Physics, 2008
We investigate the phenomenon of sudden death of entanglement in a bipartite system subjected to ... more We investigate the phenomenon of sudden death of entanglement in a bipartite system subjected to dissipative environments with arbitrary initial pure entangled state between two atoms. We find that in a vacuum reservoir the presence of the state where both atoms are in excited states is a necessary condition for the sudden death of entanglement. Otherwise entanglement remains for an infinite time and decays asymptotically with the decay of individual qubits. For pure 2-qubit entangled states in a thermal environment, we observe that the sudden death of entanglement always happens. The sudden death time of the entangled states is related to the temperature of the reservoir and the initial preparation of the entangled states.
Physical Review A, 2002
We present scheme for generation of entanglement between different modes of radiation field insid... more We present scheme for generation of entanglement between different modes of radiation field inside high-Q superconducting cavities. Our scheme is based on the interaction of a three-level atom with the cavity field for pre-calculated interaction times with each mode. This work enables us to generate complete set of Bell basis states and GHZ state.
Journal of Physics B-atomic Molecular and Optical Physics, 2008
... Qurrat-ul-Ain Gulfam1, Rameez-ul-Islam2 and Manzoor Ikram1 1 Centre for Quantum Physics, COMS... more ... Qurrat-ul-Ain Gulfam1, Rameez-ul-Islam2 and Manzoor Ikram1 1 Centre for Quantum Physics, COMSATS Institute of Information Technology, Islamabad, Pakistan 2 Photonics Division, National Institute of Lasers and Optronics, PINSTECH, Nilore, Islamabad, Pakistan ...
Journal of Modern Optics, 2009
We suggest a simple method to teleport an unknown superposition of the atomic internal state of a... more We suggest a simple method to teleport an unknown superposition of the atomic internal state of a two-level atom onto transverse atomic momenta of another atom during its flight. The scheme relies on the standard cavity QED techniques and is inherently deterministic with sufficiently high fidelity for the teleported state. It is further shown that the procedure can be straightforwardly
Journal of Physics B-atomic Molecular and Optical Physics, 2007
We propose a scheme for generating entanglement of quantum states with continuous variables (cohe... more We propose a scheme for generating entanglement of quantum states with continuous variables (coherent states and squeezed vacuum states) of electromagnetical fields. The scheme involves cross-Kerr nonlinearity. It was shown that the cross-Kerr nonlinearity required for generating the superposition and entanglement of squeezed vacuum states is smaller than that required for coherent states. It was also found that the fidelity
Journal of Optics B-quantum and Semiclassical Optics, 2004
A scheme for the measurement of the position distribution of an atom by passing it through a stan... more A scheme for the measurement of the position distribution of an atom by passing it through a standing wave field inside a cavity is discussed. The determination of the position distribution function localizes the atom within the sub-wavelength region of the standing wave. The dependence of the atom localization on the photon statistics of the cavity field is studied. The degree of resolution increases dramatically for a cascaded cavity system.
Physical Review A, 2011
Recently quantum beat lasers have been considered as a source of entangled radiation [S. Qamar, F... more Recently quantum beat lasers have been considered as a source of entangled radiation [S. Qamar, F. Ghafoor, M. Hillery, and M. S. Zubairy, Phys. Rev. APLRAAN1050-294710.1103/PhysRevA.77.062308 77, 062308 (2008)]. We investigate and quantify the entanglement of this system when the initial cavity modes are prepared in a Gaussian two-mode state, one being a nonclassical state and the other a thermal state. It is investigated how the output entanglement varies with the nonclassicality of the input Gaussian state, thermal noise, and the strength of the driving field.
Optics Communications, 2000
ABSTRACT Quantum entanglement plays a key role in many of the applications in the quantum informa... more ABSTRACT Quantum entanglement plays a key role in many of the applications in the quantum information processing system. In this paper, we present a method for preparing an entangled field state for a fixed number of photons in the two cavities.
Physical Review A, 2007
ABSTRACT We analyze the quantum correlations between side modes of a quantum beat laser when a tw... more ABSTRACT We analyze the quantum correlations between side modes of a quantum beat laser when a two-level atomic medium is driven strongly by a classical field. The squeezing and the entanglement generation of the cavity radiation are investigated. It turns out that there is neither squeezing nor entanglement when the strong driving field is resonant with the atomic transition but the generated light exhibits both two-mode squeezing and entanglement when the driving field is tuned away from the atomic transition.
Optics Communications, 2011
ABSTRACT We investigate the entanglement dynamics in a bipartite atomic system subjected to therm... more ABSTRACT We investigate the entanglement dynamics in a bipartite atomic system subjected to thermal environment with arbitrary initial pure entangled states. We consider the atoms close together and study the effect of temperature of the reservoir and the interatomic distance on the evolution of entanglement for both initially entangled and unentangled states. We find that we can have long time entanglement even in thermal environment.Research Highlights► We study the entanglement dynamics of close atoms in thermal environment. ► We see the effect of dipole-dipole interaction and collective damping on entanglement. ► We noticed that entanglement can be maintained for infinite time. ► Entanglement can be generated from initial separated states.
Physical Review A, 2004
We propose a scheme for the measurement of joint photon statistics and Wigner function of the ent... more We propose a scheme for the measurement of joint photon statistics and Wigner function of the entangled field states between two separate cavities. The scheme utilizes the momentum state of the two-level atoms in Bragg’s regime. The probability of finding the atom in any one of the momentum states is the product of joint photon statistics and an oscillatory function. The argument of the function contains the information of the joint photon numbers in two cavities. We use the method of state reduction to a single set of joint photon numbers, which is a consequence of the measuring sequence. The repeated measurement of the set of photon numbers gives the joint photon statistics of the entangled field state. The complete entangled state can be reconstructed as a Wigner function from the knowledge of photon statistics of the coherently displaced entangled state.
Journal of Physics B-atomic Molecular and Optical Physics, 2012
We propose a scheme for the quantum teleportation of an arbitrary 2N-dimensional macroscopic atom... more 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 ensemble states to photonic states
Physical Review A, 2011
Recently quantum beat lasers have been considered as a source of entangled radiation [S. Qamar, F... more Recently quantum beat lasers have been considered as a source of entangled radiation [S. Qamar, F. Ghafoor, M. Hillery, and M. S. Zubairy, Phys. Rev. A 77, 062308 ]. We investigate and quantify the entanglement of this system when the initial cavity modes are prepared in a Gaussian two-mode state, one being a nonclassical state and the other a thermal state. It is investigated how the output entanglement varies with the nonclassicality of the input Gaussian state, thermal noise, and the strength of the driving field.
International Journal of Quantum Information, 2008
A scheme for remote preparation of field (atomic) states is proposed. Protocol execution requires... more A scheme for remote preparation of field (atomic) states is proposed. Protocol execution requires cavity QED based atom-field interactions successively supplemented with Ramsey interferometry. The state to be remotely prepared at the receiver's end is acquired by deterministically manipulating the sender's component of the pre-shared entangled state. In the case of field entanglement, it is carried out with the help of an atom that passes through the sender's cavity and then traverses a classical external field for specified times prior to detection. However, for atomic entangled states, only interactions with the classical field suffice to complete the task. The scheme guarantees good success probability with high fidelity and requires one bit of classical communication.
Journal of Physics B-atomic Molecular and Optical Physics, 2007
We propose a scheme for generation of highly non-classical entangled field states of the type \fr... more We propose a scheme for generation of highly non-classical entangled field states of the type \frac{1}{\sqrt{2}}(|n,0\rangle \pm |0,n\rangle ) in the cavity QED scenario. The scheme utilizes an atomic analogue of the Mach Zehnder interferometer having a quantized field in the high-Q cavity containing a superposition of zero and one photon that acts as the first beam splitter. The probability for production of the desired states may approach a value close to unity with high fidelity under prevailing experimental conditions.
Journal of Physics B-atomic Molecular and Optical Physics, 2012
We investigate the entanglement dynamics of a bipartite atomic system, with atoms being close tog... more We investigate the entanglement dynamics of a bipartite atomic system, with atoms being close together, interacting with a common vacuum reservoir. We show that local unitary operations such as Pauli-x and Pauli-z on single or both atoms can lead to a significant positive change in the subsequent evolution of the entanglement. Sudden death of the entanglement can be delayed and
Physical Review A, 2004
We propose a scheme for the measurement of joint photon statistics and Wigner function of the ent... more We propose a scheme for the measurement of joint photon statistics and Wigner function of the entangled field states between two separate cavities. The scheme utilizes the momentum state of the two-level atoms in Bragg's regime. The probability of finding the atom in any one of the momentum states is the product of joint photon statistics and an oscillatory function.
Journal of Physics B-atomic Molecular and Optical Physics, 2008
We investigate the phenomenon of sudden death of entanglement in a bipartite system subjected to ... more We investigate the phenomenon of sudden death of entanglement in a bipartite system subjected to dissipative environments with arbitrary initial pure entangled state between two atoms. We find that in a vacuum reservoir the presence of the state where both atoms are in excited states is a necessary condition for the sudden death of entanglement. Otherwise entanglement remains for an infinite time and decays asymptotically with the decay of individual qubits. For pure 2-qubit entangled states in a thermal environment, we observe that the sudden death of entanglement always happens. The sudden death time of the entangled states is related to the temperature of the reservoir and the initial preparation of the entangled states.
Physical Review A, 2002
We present scheme for generation of entanglement between different modes of radiation field insid... more We present scheme for generation of entanglement between different modes of radiation field inside high-Q superconducting cavities. Our scheme is based on the interaction of a three-level atom with the cavity field for pre-calculated interaction times with each mode. This work enables us to generate complete set of Bell basis states and GHZ state.
Journal of Physics B-atomic Molecular and Optical Physics, 2008
... Qurrat-ul-Ain Gulfam1, Rameez-ul-Islam2 and Manzoor Ikram1 1 Centre for Quantum Physics, COMS... more ... Qurrat-ul-Ain Gulfam1, Rameez-ul-Islam2 and Manzoor Ikram1 1 Centre for Quantum Physics, COMSATS Institute of Information Technology, Islamabad, Pakistan 2 Photonics Division, National Institute of Lasers and Optronics, PINSTECH, Nilore, Islamabad, Pakistan ...
Journal of Modern Optics, 2009
We suggest a simple method to teleport an unknown superposition of the atomic internal state of a... more We suggest a simple method to teleport an unknown superposition of the atomic internal state of a two-level atom onto transverse atomic momenta of another atom during its flight. The scheme relies on the standard cavity QED techniques and is inherently deterministic with sufficiently high fidelity for the teleported state. It is further shown that the procedure can be straightforwardly
Journal of Physics B-atomic Molecular and Optical Physics, 2007
We propose a scheme for generating entanglement of quantum states with continuous variables (cohe... more We propose a scheme for generating entanglement of quantum states with continuous variables (coherent states and squeezed vacuum states) of electromagnetical fields. The scheme involves cross-Kerr nonlinearity. It was shown that the cross-Kerr nonlinearity required for generating the superposition and entanglement of squeezed vacuum states is smaller than that required for coherent states. It was also found that the fidelity
Journal of Optics B-quantum and Semiclassical Optics, 2004
A scheme for the measurement of the position distribution of an atom by passing it through a stan... more A scheme for the measurement of the position distribution of an atom by passing it through a standing wave field inside a cavity is discussed. The determination of the position distribution function localizes the atom within the sub-wavelength region of the standing wave. The dependence of the atom localization on the photon statistics of the cavity field is studied. The degree of resolution increases dramatically for a cascaded cavity system.
Physical Review A, 2011
Recently quantum beat lasers have been considered as a source of entangled radiation [S. Qamar, F... more Recently quantum beat lasers have been considered as a source of entangled radiation [S. Qamar, F. Ghafoor, M. Hillery, and M. S. Zubairy, Phys. Rev. APLRAAN1050-294710.1103/PhysRevA.77.062308 77, 062308 (2008)]. We investigate and quantify the entanglement of this system when the initial cavity modes are prepared in a Gaussian two-mode state, one being a nonclassical state and the other a thermal state. It is investigated how the output entanglement varies with the nonclassicality of the input Gaussian state, thermal noise, and the strength of the driving field.
Optics Communications, 2000
ABSTRACT Quantum entanglement plays a key role in many of the applications in the quantum informa... more ABSTRACT Quantum entanglement plays a key role in many of the applications in the quantum information processing system. In this paper, we present a method for preparing an entangled field state for a fixed number of photons in the two cavities.
Physical Review A, 2007
ABSTRACT We analyze the quantum correlations between side modes of a quantum beat laser when a tw... more ABSTRACT We analyze the quantum correlations between side modes of a quantum beat laser when a two-level atomic medium is driven strongly by a classical field. The squeezing and the entanglement generation of the cavity radiation are investigated. It turns out that there is neither squeezing nor entanglement when the strong driving field is resonant with the atomic transition but the generated light exhibits both two-mode squeezing and entanglement when the driving field is tuned away from the atomic transition.
Optics Communications, 2011
ABSTRACT We investigate the entanglement dynamics in a bipartite atomic system subjected to therm... more ABSTRACT We investigate the entanglement dynamics in a bipartite atomic system subjected to thermal environment with arbitrary initial pure entangled states. We consider the atoms close together and study the effect of temperature of the reservoir and the interatomic distance on the evolution of entanglement for both initially entangled and unentangled states. We find that we can have long time entanglement even in thermal environment.Research Highlights► We study the entanglement dynamics of close atoms in thermal environment. ► We see the effect of dipole-dipole interaction and collective damping on entanglement. ► We noticed that entanglement can be maintained for infinite time. ► Entanglement can be generated from initial separated states.
Physical Review A, 2004
We propose a scheme for the measurement of joint photon statistics and Wigner function of the ent... more We propose a scheme for the measurement of joint photon statistics and Wigner function of the entangled field states between two separate cavities. The scheme utilizes the momentum state of the two-level atoms in Bragg’s regime. The probability of finding the atom in any one of the momentum states is the product of joint photon statistics and an oscillatory function. The argument of the function contains the information of the joint photon numbers in two cavities. We use the method of state reduction to a single set of joint photon numbers, which is a consequence of the measuring sequence. The repeated measurement of the set of photon numbers gives the joint photon statistics of the entangled field state. The complete entangled state can be reconstructed as a Wigner function from the knowledge of photon statistics of the coherently displaced entangled state.
Journal of Physics B-atomic Molecular and Optical Physics, 2012
We propose a scheme for the quantum teleportation of an arbitrary 2N-dimensional macroscopic atom... more 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 ensemble states to photonic states
Physical Review A, 2011
Recently quantum beat lasers have been considered as a source of entangled radiation [S. Qamar, F... more Recently quantum beat lasers have been considered as a source of entangled radiation [S. Qamar, F. Ghafoor, M. Hillery, and M. S. Zubairy, Phys. Rev. A 77, 062308 ]. We investigate and quantify the entanglement of this system when the initial cavity modes are prepared in a Gaussian two-mode state, one being a nonclassical state and the other a thermal state. It is investigated how the output entanglement varies with the nonclassicality of the input Gaussian state, thermal noise, and the strength of the driving field.
International Journal of Quantum Information, 2008
A scheme for remote preparation of field (atomic) states is proposed. Protocol execution requires... more A scheme for remote preparation of field (atomic) states is proposed. Protocol execution requires cavity QED based atom-field interactions successively supplemented with Ramsey interferometry. The state to be remotely prepared at the receiver's end is acquired by deterministically manipulating the sender's component of the pre-shared entangled state. In the case of field entanglement, it is carried out with the help of an atom that passes through the sender's cavity and then traverses a classical external field for specified times prior to detection. However, for atomic entangled states, only interactions with the classical field suffice to complete the task. The scheme guarantees good success probability with high fidelity and requires one bit of classical communication.