For the first time we construct the eigenstate ｜τ〉 of noncommutatlve coordinate. It turns out that｜τ〉 is an entangled state in the ordinary space. Remarkably, its Schmidt decomposition has definite expression in...For the first time we construct the eigenstate ｜τ〉 of noncommutatlve coordinate. It turns out that｜τ〉 is an entangled state in the ordinary space. Remarkably, its Schmidt decomposition has definite expression in the coordinate representation and the momentum representation. The 〈τ｜ representation can simplify some calculations for obtaining energy level of two-dimensional oscillator in noncommutative space.展开更多
We propose a new scheme for realizing deterministic quantum state transfer （QST） between two spatially separated single molecule magnets （SMMs） with the framework of cavity quantum eleetrodynamics （QED）. In the ...We propose a new scheme for realizing deterministic quantum state transfer （QST） between two spatially separated single molecule magnets （SMMs） with the framework of cavity quantum eleetrodynamics （QED）. In the present scheme, two SMMs are trapped in two spatially separated optical cavities coupled by an optical fiber. Through strictly numerically simulating, we demonstrate that our scheme is robust with respect to the SMMs＇ spontaneous decay and fiber loss under the conditions of dispersive SMMs-field interaction and strong coupling of cavity fiber. In addition, we also discuss the influence of photon leakage out of cavities and show that our proposal is good enough to demonstrate the generation of QST with high fidelity utilizing the current experimental technology. The present investigation provides research opportunities for realizing QST between solid-state qubits and may result in a substantial impact on the progress of solid-state-based quantum communications network.展开更多
We introduce a kind of number-conserving coherent state in Rindler space which can describe the quantum state of thermal particles observed in Rindler space. This is based on the Unruh effect that the thermal particle...We introduce a kind of number-conserving coherent state in Rindler space which can describe the quantum state of thermal particles observed in Rindler space. This is based on the Unruh effect that the thermal particles seen by an accelerating observer in fiat space can be seen by an inertial observer in curved space under a conformal transformation.展开更多
It has been shown that a quantum state could be perfectly transferred via a spin chain with engineered'always-on interaction'.In this paper,we study a more realistic problem for such a quantum state transfer (...It has been shown that a quantum state could be perfectly transferred via a spin chain with engineered'always-on interaction'.In this paper,we study a more realistic problem for such a quantum state transfer (QST)protocol,how the efficacy of QST is reduced by the quantum decoherence induced by a spatially distributed environment.Here,the environment is universally modeled as a bath of fermions located in different positions.By making use of theirreducible tensor method in angular momentum theory,we investigate the effect of environment on the efficiency of QSTfor both cases at zero and finite temperatures.We not only show the generic exponential decay of QST efficiency as thenumber of sites increase,but also find some counterintuitive effect,the QST can be enhanced as temperature increasesin some cases.展开更多
The entanglement evolution of multipartite quantum states under a spin environment is analyzed. Due to interaction, the extent to which the entanglement vanishes depends not only on the size of system and the structur...The entanglement evolution of multipartite quantum states under a spin environment is analyzed. Due to interaction, the extent to which the entanglement vanishes depends not only on the size of system and the structure of quantum states, but also on the exchange couplings with environment. The decoherence-free subspaces have been identified by using the linear entropy.展开更多
We focus on a new gauge symmetry keeping regularization scheme for momentum integration and point out that dropping out momentum space asymptotic non-logarithmic total derivative divergent integrations in quantum fiel...We focus on a new gauge symmetry keeping regularization scheme for momentum integration and point out that dropping out momentum space asymptotic non-logarithmic total derivative divergent integrations in quantum field theory is a simple and natural way to keep the computation program gauge-covariant.展开更多
Potential electric and gravitational fields do not change steady quantized states of electrons in chemical bonds, microscopic clusters of charges and macroscopic superconducting rings. There are no theoretical grounds...Potential electric and gravitational fields do not change steady quantized states of electrons in chemical bonds, microscopic clusters of charges and macroscopic superconducting rings. There are no theoretical grounds to create Squid-type instruments to measure electric and gravitational fields with quantum accuracy basing on the Bohr-Sommerfeld quantization of charged particles. Squid-verified spatial flatness for superfluid electrons corresponds to the material space paradigm for reality.展开更多
A scheme is presented to realize the controlled teleportation of an unknown three dimensional(3D) two-particle state by using a non-maximally entangled two-particle state and a non-maximally entangled three-particle s...A scheme is presented to realize the controlled teleportation of an unknown three dimensional(3D) two-particle state by using a non-maximally entangled two-particle state and a non-maximally entangled three-particle state in the 3D space as the quantum channels,and one of the particles in the channels is used as the controlled particle.Analysis shows that when the quantum channels are of maximal entanglement,namely the channels are composed of a 3D Bell state and a 3D GHZ state,the total success probability of the controlled teleportation can reach 1.And this scheme can be expanded to control the teleportation of an unknown D-dimensional two-particle state.展开更多
In this paper we have studied the dynamical evolution of Shannon information entropies in position and momentum spaces for two classes of（nonstationary） atom-field entangled states,which are obtained via the JaynesC...In this paper we have studied the dynamical evolution of Shannon information entropies in position and momentum spaces for two classes of（nonstationary） atom-field entangled states,which are obtained via the JaynesCummings model and its generalization.We have focused on the interaction between two- and（1）-type three-level atoms with the single-mode quantized field.The three-dimensional plots of entropy densities in position and momentum spaces are presented versus corresponding coordinates and time,numerically.It is observed that for particular values of the parameters of the systems,the entropy squeezing in position space occurs.Finally,we have shown that the well-known BBM（Beckner,Bialynicki-Birola and Mycielsky） inequality,which is a stronger statement of the Heisenberg uncertainty relation,is properly satisfied.展开更多
基金The project supported by Specialized Research Fund for the Doctorial Progress of Higher Education （SRFDP） under Grant No. 2004035819
文摘For the first time we construct the eigenstate ｜τ〉 of noncommutatlve coordinate. It turns out that｜τ〉 is an entangled state in the ordinary space. Remarkably, its Schmidt decomposition has definite expression in the coordinate representation and the momentum representation. The 〈τ｜ representation can simplify some calculations for obtaining energy level of two-dimensional oscillator in noncommutative space.
基金Supported by the Natural Science Foundation of China under Grant Nos.10575040,90503010,10634060,and 10874050 National Basic Research Program of China under Grant No.2005CB724508+1 种基金the Foundation from the Ministry of the National Education of China under Grant No.200804870051 the Science Innovation Foundation of Huazhong University of Science and Technology under Grant No.HF-06-010-08-012
文摘We propose a new scheme for realizing deterministic quantum state transfer （QST） between two spatially separated single molecule magnets （SMMs） with the framework of cavity quantum eleetrodynamics （QED）. In the present scheme, two SMMs are trapped in two spatially separated optical cavities coupled by an optical fiber. Through strictly numerically simulating, we demonstrate that our scheme is robust with respect to the SMMs＇ spontaneous decay and fiber loss under the conditions of dispersive SMMs-field interaction and strong coupling of cavity fiber. In addition, we also discuss the influence of photon leakage out of cavities and show that our proposal is good enough to demonstrate the generation of QST with high fidelity utilizing the current experimental technology. The present investigation provides research opportunities for realizing QST between solid-state qubits and may result in a substantial impact on the progress of solid-state-based quantum communications network.
基金Supported by the National Natural Science Foundation of China under Grant Nos.10775097 and 10874174by the Specialized Research Fund for the for the Doctorial Progress of Higher Education of China under Grant No.20070358009
文摘We introduce a kind of number-conserving coherent state in Rindler space which can describe the quantum state of thermal particles observed in Rindler space. This is based on the Unruh effect that the thermal particles seen by an accelerating observer in fiat space can be seen by an inertial observer in curved space under a conformal transformation.
基金Supported by the NSFC under Grant Nos.10775048,10704023NFRPC under Grant No.2007CB925204+1 种基金New Century Excellent Talents in University under Grant No.NCET-08-0682the Scientific Research Fund of Hunan Provincial Education Department of China under Grant No.07C579
文摘It has been shown that a quantum state could be perfectly transferred via a spin chain with engineered'always-on interaction'.In this paper,we study a more realistic problem for such a quantum state transfer (QST)protocol,how the efficacy of QST is reduced by the quantum decoherence induced by a spatially distributed environment.Here,the environment is universally modeled as a bath of fermions located in different positions.By making use of theirreducible tensor method in angular momentum theory,we investigate the effect of environment on the efficiency of QSTfor both cases at zero and finite temperatures.We not only show the generic exponential decay of QST efficiency as thenumber of sites increase,but also find some counterintuitive effect,the QST can be enhanced as temperature increasesin some cases.
基金The project supported by the State Key Basic Research Programme of China under Grant No. 2001CB309310 and National Natural Science Foundation of China under Grant Nos. 60173047 and 60573008
文摘The entanglement evolution of multipartite quantum states under a spin environment is analyzed. Due to interaction, the extent to which the entanglement vanishes depends not only on the size of system and the structure of quantum states, but also on the exchange couplings with environment. The decoherence-free subspaces have been identified by using the linear entropy.
基金National Natural Science Foundation of China under Grant No.10435040
文摘We focus on a new gauge symmetry keeping regularization scheme for momentum integration and point out that dropping out momentum space asymptotic non-logarithmic total derivative divergent integrations in quantum field theory is a simple and natural way to keep the computation program gauge-covariant.
文摘Potential electric and gravitational fields do not change steady quantized states of electrons in chemical bonds, microscopic clusters of charges and macroscopic superconducting rings. There are no theoretical grounds to create Squid-type instruments to measure electric and gravitational fields with quantum accuracy basing on the Bohr-Sommerfeld quantization of charged particles. Squid-verified spatial flatness for superfluid electrons corresponds to the material space paradigm for reality.
基金supported by the National High Technology Research and Development Program of China (Nos.2007AA030112 and2009AA032708)
文摘A scheme is presented to realize the controlled teleportation of an unknown three dimensional(3D) two-particle state by using a non-maximally entangled two-particle state and a non-maximally entangled three-particle state in the 3D space as the quantum channels,and one of the particles in the channels is used as the controlled particle.Analysis shows that when the quantum channels are of maximal entanglement,namely the channels are composed of a 3D Bell state and a 3D GHZ state,the total success probability of the controlled teleportation can reach 1.And this scheme can be expanded to control the teleportation of an unknown D-dimensional two-particle state.
文摘In this paper we have studied the dynamical evolution of Shannon information entropies in position and momentum spaces for two classes of（nonstationary） atom-field entangled states,which are obtained via the JaynesCummings model and its generalization.We have focused on the interaction between two- and（1）-type three-level atoms with the single-mode quantized field.The three-dimensional plots of entropy densities in position and momentum spaces are presented versus corresponding coordinates and time,numerically.It is observed that for particular values of the parameters of the systems,the entropy squeezing in position space occurs.Finally,we have shown that the well-known BBM（Beckner,Bialynicki-Birola and Mycielsky） inequality,which is a stronger statement of the Heisenberg uncertainty relation,is properly satisfied.
