Mang Feng - Profile on Academia.edu (original) (raw)

Papers by Mang Feng

Research paper thumbnail of Quantum gates using electronic and nuclear spins of Yb+ in a magnetic field gradient

The European Physical Journal D, 2011

An efficient scheme is proposed to carry out gate operations on an array of trapped Yb + ions, ba... more An efficient scheme is proposed to carry out gate operations on an array of trapped Yb + ions, based on a previous proposal using both electronic and nuclear degrees of freedom in a magnetic field gradient. For this purpose we consider the Paschen-Back regime (strong magnetic field) and employ a high-field approximation in this treatment. We show the possibility to suppress the unwanted coupling between the electron spins by appropriately swapping states between electronic and nuclear spins. The feasibility of generating the required high magnetic field is discussed.

Research paper thumbnail of Superdense Coding via Hot Trapped Ions

Superdense Coding via Hot Trapped Ions

Communications in Theoretical Physics, 2004

ABSTRACT

Research paper thumbnail of Simple Approach to the Solution of a Trapped and Radiated Cold Ion Beyond the Lamb–Dicke Limit

Simple Approach to the Solution of a Trapped and Radiated Cold Ion Beyond the Lamb–Dicke Limit

Communications in Theoretical Physics, 2002

ABSTRACT

Research paper thumbnail of Effect of the Double Frequency of Trap Field in a Paul Trap

Effect of the Double Frequency of Trap Field in a Paul Trap

Communications in Theoretical Physics, 2001

ABSTRACT

Research paper thumbnail of Stabilizing Chaos in the rf-Driven Josephson Junction

Stabilizing Chaos in the rf-Driven Josephson Junction

Communications in Theoretical Physics, 2000

ABSTRACT

Research paper thumbnail of Series solution of two trapped ions experiencing the standing wave of a resonant laser

Series solution of two trapped ions experiencing the standing wave of a resonant laser

Physics Letters A, 1999

Two identical two-level ions driven by a standing wave laser on resonance in a harmonic trap are ... more Two identical two-level ions driven by a standing wave laser on resonance in a harmonic trap are investigated in the Lamb–Dicke limit and weak excitation regime. We present series solutions of such a system for the trap center staying at a node of the standing wave.

Research paper thumbnail of Non-Markovian decoherence dynamics of entangled coherent states

We microscopically model the decoherence dynamics of entangled coherent states of two optical mod... more We microscopically model the decoherence dynamics of entangled coherent states of two optical modes under the influence of vacuum fluctuation. We derive an exact master equation with time-dependent coefficients reflecting the memory effect of the environment, by using the Feynman-Vernon influence functional theory in the coherent-state representation. Under the Markovian approximation, our master equation recovers the widely used Lindblad equation in quantum optics. We then investigate the non-Markovian entanglement dynamics of the two-mode entangled coherent states under vacuum fluctuation. Compared with the results in Markovian limit, it shows that the non-Markovian effect enhances the disentanglement to the initially entangled coherent state. Our analysis also shows that the decoherence behaviors of the entangled coherent states depend on the symmetrical properties of the entangled coherent states as well as the couplings between the optical fields and the environment.

Research paper thumbnail of Fast optical cooling of nanomechanical cantilever with the dynamical Zeeman effect

Optics express, Jan 2, 2013

We propose an efficient optical electromagnetically induced transparency (EIT) cooling scheme for... more We propose an efficient optical electromagnetically induced transparency (EIT) cooling scheme for a cantilever with a nitrogen-vacancy center attached in a non-uniform magnetic field using dynamical Zeeman effect. In our scheme, the Zeeman effect combined with the quantum interference effect enhances the desired cooling transition and suppresses the undesired heating transitions. As a result, the cantilever can be cooled down to nearly the vibrational ground state under realistic experimental conditions within a short time. This efficient optical EIT cooling scheme can be reduced to the typical EIT cooling scheme under special conditions.

Research paper thumbnail of Exhibition of the periodicity of Quantum Fourier Transformation in Nuclear Magnetic Resonance

The remarkable capability of quantum Fourier transformation (QFT) to extract the periodicity of a... more The remarkable capability of quantum Fourier transformation (QFT) to extract the periodicity of a given periodic function has been exhibited by using nuclear magnetic resonance (NMR) techniques. Two separate sets of experiments were performed. In a full QFT, the periodicity were validated with state tomography and fidelity measurements. For a simplified QFT, the three-qubit pseudo-pure state was created by introducting

Research paper thumbnail of One-step generation of multipartite entanglement among nitrogen-vacancy center ensembles

One-step generation of multipartite entanglement among nitrogen-vacancy center ensembles

Scientific Reports, 2015

We describe a one-step, deterministic and scalable scheme for creating macroscopic arbitrary enta... more We describe a one-step, deterministic and scalable scheme for creating macroscopic arbitrary entangled coherent states (ECSs) of separate nitrogen-vacancy center ensembles (NVEs) that couple to a superconducting flux qubit. We discuss how to generate the entangled states between the flux qubit and two NVEs by the resonant driving. Then the ECSs of the NVEs can be obtained by projecting the flux qubit, and the entanglement detection can be realized by transferring the quantum state from the NVEs to the flux qubit. Our numerical simulation shows that even under current experimental parameters the concurrence of the ECSs can approach unity. We emphasize that this method is straightforwardly extendable to the case of many NVEs.

Research paper thumbnail of Quantum Algorithms and Mathematical Formulations of Bio-Molecular Solutions of the Vertex Cover Problem in the Finite-Dimensional Hilbert Space

IEEE transactions on nanobioscience, Jan 5, 2014

In this paper, it is shown that the proposed quantum algorithm for implementing Boolean circuits ... more In this paper, it is shown that the proposed quantum algorithm for implementing Boolean circuits generated from the DNA-based algorithm solving the vertex-cover problem of any graph G with m edges and n vertices is the optimal quantum algorithm. Next, it is also demonstrated that mathematical solutions of the same bio-molecular solutions are represented in terms of a unit vector in the finite-dimensional Hilbert space. Furthermore, for testing our theory, a nuclear magnetic resonance (NMR) experiment of three quantum bits to solve the simplest vertex-cover problem is completed.

Research paper thumbnail of Quantum algorithms of the vertex cover problem on a quantum computer

In the field of molecular computing, one of the interesting open questions is to ask what mathema... more In the field of molecular computing, one of the interesting open questions is to ask what mathematical solutions of bio-molecular solutions for dealing with any NP-Complete problem are. In this paper, it is proved that for solving the vertex-cover problem of any graph G with m edges and n vertices, bio-molecular solutions are implemented by the proposed quantum algorithm and mathematical solutions of the same bio-molecular solutions are represented in term of a unit vector in the finite-dimensional Hilbert space. Next, it is also demonstrated that for solving the same problem, the proposed quantum algorithm can be also implemented by means of biological operations and DNA sequences and its mathematical representation that is in term of a unit vector in the Hilbert space also can also be encoded by DNA strands and biological operations. Next, it is assumed that any other NP-complete problem can be reduced to the vertex-cover problem with a polynomial time algorithm in a general electronic computer and it is shown for an extension of Cook's Theorem that if the size of a reduced NP-complete problem is not equal to or less than that of the vertex-cover problem, then a new quantum algorithm of solving any other NP-complete problem with a quadratic speed-up should be developed. Furthermore, for testing our theory, a three-qubit nuclear magnetic resonance (NMR) experiment of solving the simplest vertex-cover problem is performed.

Research paper thumbnail of Non-Markovian effect on the quantum discord

Physical Review A, 2010

We study the non-Markovian effect on the dynamics of the quantum discord by exactly solving a mod... more We study the non-Markovian effect on the dynamics of the quantum discord by exactly solving a model consisting of two independent qubits subject to two zero-temperature non-Markovian reservoirs, respectively. Considering the two qubits initially prepared in Bell-like or extended Werner-like states, we show that there is no occurrence of the sudden death, but only instantaneous disappearance of the quantum discord at some time points, in comparison to the entanglement sudden death in the same range of the parameters of interest. It implies that the quantum discord is more useful than the entanglement to describe quantum correlation involved in quantum systems. PACS numbers: 03.65.Yz, 03.67.-a , 03.65.Ta

Research paper thumbnail of Systematic QSOs emission line shifts caused by a high-temperature mechanism

Systematic QSOs emission line shifts caused by a high-temperature mechanism

Il Nuovo Cimento B, 1996

Summary The observed results exhibit the fact that there are some systematic effects in QSOs spe... more Summary The observed results exhibit the fact that there are some systematic effects in QSOs spectra, such as: a) the different emission lines give different red-shifts; b) high-ionization lines (HILs) CIV λ1549, NV, CIII] X.1909 and possiblyLy α are systematically blue-shifted to a velocity of about 600 km s−1 with respect to low-ionization lines (LILs) 01, Mgll λ2798 and the balmer

Research paper thumbnail of Simultaneous intraportation of many quantum states within the quantum computing network

Physics Letters A, 2001

A scheme is proposed for simultaneous intraportation of many unknown quantum states within a quan... more A scheme is proposed for simultaneous intraportation of many unknown quantum states within a quantum computing network. It is shown that our scheme, much different from the teleportation in the strict sense, can be very similar to the original teleportation proposal (Phys. Rev. Lett. 70 (1993) 1895) and the efficiency of the scheme for quantum state transmission is very high. The possible applications of our scheme are also discussed.  2001 Elsevier Science B.V. All rights reserved. PACS: 03.65.Bz; 42.50.Dv; 89.70.+c Quantum computing [1] is an interesting and hot topic in the quantum theory, which can treat efficiently some nondeterministic polynomial-time problems inaccessible for the existing computer, such as factorization of large numbers [2], or solve some problems more rapidly, e.g., searching a certain item from a large disordered system [3], etc. It has been proven that any operation in the quantum computing can be decomposed into a series of two basic operations [4]. One is controlled-NOT (CN) gate, defined as | 1 | 2 → | 1 | 1 ⊕ 2 with 1,2 = 0, 1, and the other is Hadamard gate 0375-9601/01/$ -see front matter  2001 Elsevier Science B.V. All rights reserved. PII: S 0 3 7 5 -9 6 0 1 ( 0 1 ) 0 0 1 7 0 -0

Research paper thumbnail of Experimental implementation of remote state preparation by nuclear magnetic resonance

Physics Letters A, 2003

We have experimentally implemented remote state preparation (RSP) of a qubit from a hydrogen to a... more We have experimentally implemented remote state preparation (RSP) of a qubit from a hydrogen to a carbon nucleus in molecules of carbon-13 labeled chloroform 13 CHCl 3 over interatomic distances using liquid-state nuclear magnetic resonance (NMR) technique. Full RSP of a special ensemble of qubits, i.e., a qubit chosen from equatorial and polar great circles on a Bloch sphere with Pati's scheme, was achieved with one cbit communication. Such a RSP scheme can be generalized to prepare a large number of qubit states and may be used in other quantum information processing and quantum computing.

Research paper thumbnail of Sudden death and birth of entanglement beyond the Markovian approximation

Physics Letters A, 2009

We investigate the entanglement dynamics of two initially entangled qubits interacting independen... more We investigate the entanglement dynamics of two initially entangled qubits interacting independently with two uncorrelated reservoirs beyond the Markovian approximation. Quite different from the Markovian reservoirs [C. E. López et al., Phys. Rev. Lett. 101 (2008) 080503], we find that entanglement sudden birth (ESB) of the two reservoirs occurs without certain symmetry with respect to the entanglement sudden death (ESD) of the two qubits. A phenomenological interpretation of entanglement revival is also given. (M. Feng) We are aware of two very recent papers: Phys. Rev. A 79 (2009) 012301 and Phys. Rev. A 79 (2009) 042302 which addressed similar topics in entanglement revival of two qubits shared with a common reservoir.

Research paper thumbnail of Stationary system of a two-level atom interacting with a single-mode phonon

Physics Letters A, 1998

We use three methods to calculate the ground state energy of the stationary system of a two-level... more We use three methods to calculate the ground state energy of the stationary system of a two-level atom interacting with a single-mode phonon. The results indicate that the variational method and the perturbation method are comparable to the exact power series solution in a wide parameter range. This might be useful for the time-dependent system. @ 1998 Elsevier Science B.V.

Research paper thumbnail of Teleportation with trapped ions in a magnetic field gradient

Physics Letters A, 2005

By means of the Ising terms generated by Coulomb interaction between ions and the magnetic field ... more By means of the Ising terms generated by Coulomb interaction between ions and the magnetic field gradient, we carry out teleportation with insurance with trapped ions. We show the feasibility and the favorable feature of our scheme by comparing with the recently achieved teleportation experiments with trapped ions. * Electronic address: dengzhijiao926@163.com

Research paper thumbnail of A variational study of the self-trapped magnetic polaron formation in double-exchange model

A variational study of the self-trapped magnetic polaron formation in double-exchange model

Physics Letters A, 2005

We study the formation of self-trapped magnetic polaron (STMP) in an antiferro/ferromagnetic doub... more We study the formation of self-trapped magnetic polaron (STMP) in an antiferro/ferromagnetic double-exchange model semi-analytically by variational solutions. It is shown that the Jahn–Teller effect is not essential to the STMP formation and the STMP forms in the antiferromagnetic material within the region of the order of the lattice constant. We also confirm that no ground state STMP exists in the ferromagnetic background, but the ground state bound MP could appear due to the impurity potential.

Research paper thumbnail of Quantum gates using electronic and nuclear spins of Yb+ in a magnetic field gradient

The European Physical Journal D, 2011

An efficient scheme is proposed to carry out gate operations on an array of trapped Yb + ions, ba... more An efficient scheme is proposed to carry out gate operations on an array of trapped Yb + ions, based on a previous proposal using both electronic and nuclear degrees of freedom in a magnetic field gradient. For this purpose we consider the Paschen-Back regime (strong magnetic field) and employ a high-field approximation in this treatment. We show the possibility to suppress the unwanted coupling between the electron spins by appropriately swapping states between electronic and nuclear spins. The feasibility of generating the required high magnetic field is discussed.

Research paper thumbnail of Superdense Coding via Hot Trapped Ions

Superdense Coding via Hot Trapped Ions

Communications in Theoretical Physics, 2004

ABSTRACT

Research paper thumbnail of Simple Approach to the Solution of a Trapped and Radiated Cold Ion Beyond the Lamb–Dicke Limit

Simple Approach to the Solution of a Trapped and Radiated Cold Ion Beyond the Lamb–Dicke Limit

Communications in Theoretical Physics, 2002

ABSTRACT

Research paper thumbnail of Effect of the Double Frequency of Trap Field in a Paul Trap

Effect of the Double Frequency of Trap Field in a Paul Trap

Communications in Theoretical Physics, 2001

ABSTRACT

Research paper thumbnail of Stabilizing Chaos in the rf-Driven Josephson Junction

Stabilizing Chaos in the rf-Driven Josephson Junction

Communications in Theoretical Physics, 2000

ABSTRACT

Research paper thumbnail of Series solution of two trapped ions experiencing the standing wave of a resonant laser

Series solution of two trapped ions experiencing the standing wave of a resonant laser

Physics Letters A, 1999

Two identical two-level ions driven by a standing wave laser on resonance in a harmonic trap are ... more Two identical two-level ions driven by a standing wave laser on resonance in a harmonic trap are investigated in the Lamb–Dicke limit and weak excitation regime. We present series solutions of such a system for the trap center staying at a node of the standing wave.

Research paper thumbnail of Non-Markovian decoherence dynamics of entangled coherent states

We microscopically model the decoherence dynamics of entangled coherent states of two optical mod... more We microscopically model the decoherence dynamics of entangled coherent states of two optical modes under the influence of vacuum fluctuation. We derive an exact master equation with time-dependent coefficients reflecting the memory effect of the environment, by using the Feynman-Vernon influence functional theory in the coherent-state representation. Under the Markovian approximation, our master equation recovers the widely used Lindblad equation in quantum optics. We then investigate the non-Markovian entanglement dynamics of the two-mode entangled coherent states under vacuum fluctuation. Compared with the results in Markovian limit, it shows that the non-Markovian effect enhances the disentanglement to the initially entangled coherent state. Our analysis also shows that the decoherence behaviors of the entangled coherent states depend on the symmetrical properties of the entangled coherent states as well as the couplings between the optical fields and the environment.

Research paper thumbnail of Fast optical cooling of nanomechanical cantilever with the dynamical Zeeman effect

Optics express, Jan 2, 2013

We propose an efficient optical electromagnetically induced transparency (EIT) cooling scheme for... more We propose an efficient optical electromagnetically induced transparency (EIT) cooling scheme for a cantilever with a nitrogen-vacancy center attached in a non-uniform magnetic field using dynamical Zeeman effect. In our scheme, the Zeeman effect combined with the quantum interference effect enhances the desired cooling transition and suppresses the undesired heating transitions. As a result, the cantilever can be cooled down to nearly the vibrational ground state under realistic experimental conditions within a short time. This efficient optical EIT cooling scheme can be reduced to the typical EIT cooling scheme under special conditions.

Research paper thumbnail of Exhibition of the periodicity of Quantum Fourier Transformation in Nuclear Magnetic Resonance

The remarkable capability of quantum Fourier transformation (QFT) to extract the periodicity of a... more The remarkable capability of quantum Fourier transformation (QFT) to extract the periodicity of a given periodic function has been exhibited by using nuclear magnetic resonance (NMR) techniques. Two separate sets of experiments were performed. In a full QFT, the periodicity were validated with state tomography and fidelity measurements. For a simplified QFT, the three-qubit pseudo-pure state was created by introducting

Research paper thumbnail of One-step generation of multipartite entanglement among nitrogen-vacancy center ensembles

One-step generation of multipartite entanglement among nitrogen-vacancy center ensembles

Scientific Reports, 2015

We describe a one-step, deterministic and scalable scheme for creating macroscopic arbitrary enta... more We describe a one-step, deterministic and scalable scheme for creating macroscopic arbitrary entangled coherent states (ECSs) of separate nitrogen-vacancy center ensembles (NVEs) that couple to a superconducting flux qubit. We discuss how to generate the entangled states between the flux qubit and two NVEs by the resonant driving. Then the ECSs of the NVEs can be obtained by projecting the flux qubit, and the entanglement detection can be realized by transferring the quantum state from the NVEs to the flux qubit. Our numerical simulation shows that even under current experimental parameters the concurrence of the ECSs can approach unity. We emphasize that this method is straightforwardly extendable to the case of many NVEs.

Research paper thumbnail of Quantum Algorithms and Mathematical Formulations of Bio-Molecular Solutions of the Vertex Cover Problem in the Finite-Dimensional Hilbert Space

IEEE transactions on nanobioscience, Jan 5, 2014

In this paper, it is shown that the proposed quantum algorithm for implementing Boolean circuits ... more In this paper, it is shown that the proposed quantum algorithm for implementing Boolean circuits generated from the DNA-based algorithm solving the vertex-cover problem of any graph G with m edges and n vertices is the optimal quantum algorithm. Next, it is also demonstrated that mathematical solutions of the same bio-molecular solutions are represented in terms of a unit vector in the finite-dimensional Hilbert space. Furthermore, for testing our theory, a nuclear magnetic resonance (NMR) experiment of three quantum bits to solve the simplest vertex-cover problem is completed.

Research paper thumbnail of Quantum algorithms of the vertex cover problem on a quantum computer

In the field of molecular computing, one of the interesting open questions is to ask what mathema... more In the field of molecular computing, one of the interesting open questions is to ask what mathematical solutions of bio-molecular solutions for dealing with any NP-Complete problem are. In this paper, it is proved that for solving the vertex-cover problem of any graph G with m edges and n vertices, bio-molecular solutions are implemented by the proposed quantum algorithm and mathematical solutions of the same bio-molecular solutions are represented in term of a unit vector in the finite-dimensional Hilbert space. Next, it is also demonstrated that for solving the same problem, the proposed quantum algorithm can be also implemented by means of biological operations and DNA sequences and its mathematical representation that is in term of a unit vector in the Hilbert space also can also be encoded by DNA strands and biological operations. Next, it is assumed that any other NP-complete problem can be reduced to the vertex-cover problem with a polynomial time algorithm in a general electronic computer and it is shown for an extension of Cook's Theorem that if the size of a reduced NP-complete problem is not equal to or less than that of the vertex-cover problem, then a new quantum algorithm of solving any other NP-complete problem with a quadratic speed-up should be developed. Furthermore, for testing our theory, a three-qubit nuclear magnetic resonance (NMR) experiment of solving the simplest vertex-cover problem is performed.

Research paper thumbnail of Non-Markovian effect on the quantum discord

Physical Review A, 2010

We study the non-Markovian effect on the dynamics of the quantum discord by exactly solving a mod... more We study the non-Markovian effect on the dynamics of the quantum discord by exactly solving a model consisting of two independent qubits subject to two zero-temperature non-Markovian reservoirs, respectively. Considering the two qubits initially prepared in Bell-like or extended Werner-like states, we show that there is no occurrence of the sudden death, but only instantaneous disappearance of the quantum discord at some time points, in comparison to the entanglement sudden death in the same range of the parameters of interest. It implies that the quantum discord is more useful than the entanglement to describe quantum correlation involved in quantum systems. PACS numbers: 03.65.Yz, 03.67.-a , 03.65.Ta

Research paper thumbnail of Systematic QSOs emission line shifts caused by a high-temperature mechanism

Systematic QSOs emission line shifts caused by a high-temperature mechanism

Il Nuovo Cimento B, 1996

Summary The observed results exhibit the fact that there are some systematic effects in QSOs spe... more Summary The observed results exhibit the fact that there are some systematic effects in QSOs spectra, such as: a) the different emission lines give different red-shifts; b) high-ionization lines (HILs) CIV λ1549, NV, CIII] X.1909 and possiblyLy α are systematically blue-shifted to a velocity of about 600 km s−1 with respect to low-ionization lines (LILs) 01, Mgll λ2798 and the balmer

Research paper thumbnail of Simultaneous intraportation of many quantum states within the quantum computing network

Physics Letters A, 2001

A scheme is proposed for simultaneous intraportation of many unknown quantum states within a quan... more A scheme is proposed for simultaneous intraportation of many unknown quantum states within a quantum computing network. It is shown that our scheme, much different from the teleportation in the strict sense, can be very similar to the original teleportation proposal (Phys. Rev. Lett. 70 (1993) 1895) and the efficiency of the scheme for quantum state transmission is very high. The possible applications of our scheme are also discussed.  2001 Elsevier Science B.V. All rights reserved. PACS: 03.65.Bz; 42.50.Dv; 89.70.+c Quantum computing [1] is an interesting and hot topic in the quantum theory, which can treat efficiently some nondeterministic polynomial-time problems inaccessible for the existing computer, such as factorization of large numbers [2], or solve some problems more rapidly, e.g., searching a certain item from a large disordered system [3], etc. It has been proven that any operation in the quantum computing can be decomposed into a series of two basic operations [4]. One is controlled-NOT (CN) gate, defined as | 1 | 2 → | 1 | 1 ⊕ 2 with 1,2 = 0, 1, and the other is Hadamard gate 0375-9601/01/$ -see front matter  2001 Elsevier Science B.V. All rights reserved. PII: S 0 3 7 5 -9 6 0 1 ( 0 1 ) 0 0 1 7 0 -0

Research paper thumbnail of Experimental implementation of remote state preparation by nuclear magnetic resonance

Physics Letters A, 2003

We have experimentally implemented remote state preparation (RSP) of a qubit from a hydrogen to a... more We have experimentally implemented remote state preparation (RSP) of a qubit from a hydrogen to a carbon nucleus in molecules of carbon-13 labeled chloroform 13 CHCl 3 over interatomic distances using liquid-state nuclear magnetic resonance (NMR) technique. Full RSP of a special ensemble of qubits, i.e., a qubit chosen from equatorial and polar great circles on a Bloch sphere with Pati's scheme, was achieved with one cbit communication. Such a RSP scheme can be generalized to prepare a large number of qubit states and may be used in other quantum information processing and quantum computing.

Research paper thumbnail of Sudden death and birth of entanglement beyond the Markovian approximation

Physics Letters A, 2009

We investigate the entanglement dynamics of two initially entangled qubits interacting independen... more We investigate the entanglement dynamics of two initially entangled qubits interacting independently with two uncorrelated reservoirs beyond the Markovian approximation. Quite different from the Markovian reservoirs [C. E. López et al., Phys. Rev. Lett. 101 (2008) 080503], we find that entanglement sudden birth (ESB) of the two reservoirs occurs without certain symmetry with respect to the entanglement sudden death (ESD) of the two qubits. A phenomenological interpretation of entanglement revival is also given. (M. Feng) We are aware of two very recent papers: Phys. Rev. A 79 (2009) 012301 and Phys. Rev. A 79 (2009) 042302 which addressed similar topics in entanglement revival of two qubits shared with a common reservoir.

Research paper thumbnail of Stationary system of a two-level atom interacting with a single-mode phonon

Physics Letters A, 1998

We use three methods to calculate the ground state energy of the stationary system of a two-level... more We use three methods to calculate the ground state energy of the stationary system of a two-level atom interacting with a single-mode phonon. The results indicate that the variational method and the perturbation method are comparable to the exact power series solution in a wide parameter range. This might be useful for the time-dependent system. @ 1998 Elsevier Science B.V.

Research paper thumbnail of Teleportation with trapped ions in a magnetic field gradient

Physics Letters A, 2005

By means of the Ising terms generated by Coulomb interaction between ions and the magnetic field ... more By means of the Ising terms generated by Coulomb interaction between ions and the magnetic field gradient, we carry out teleportation with insurance with trapped ions. We show the feasibility and the favorable feature of our scheme by comparing with the recently achieved teleportation experiments with trapped ions. * Electronic address: dengzhijiao926@163.com

Research paper thumbnail of A variational study of the self-trapped magnetic polaron formation in double-exchange model

A variational study of the self-trapped magnetic polaron formation in double-exchange model

Physics Letters A, 2005

We study the formation of self-trapped magnetic polaron (STMP) in an antiferro/ferromagnetic doub... more We study the formation of self-trapped magnetic polaron (STMP) in an antiferro/ferromagnetic double-exchange model semi-analytically by variational solutions. It is shown that the Jahn–Teller effect is not essential to the STMP formation and the STMP forms in the antiferromagnetic material within the region of the order of the lattice constant. We also confirm that no ground state STMP exists in the ferromagnetic background, but the ground state bound MP could appear due to the impurity potential.