In this paper,two-mode displaced excited squeezed vacuum states (TDESVS) are constructed and theirnormalization and completeness are investigated.Using the entangled state representation and Weyl ordering formof the W...In this paper,two-mode displaced excited squeezed vacuum states (TDESVS) are constructed and theirnormalization and completeness are investigated.Using the entangled state representation and Weyl ordering formof the Wigner operator,the Wigner functions of TDESVS are obtained and the variations of Wigner functions withthe parameters m,n and r are investigated.Besides,two marginal distributions of Wigner functions of TDESVS areobtained,which exhibit some entangled properties of the two-particle's system in TDESVS.展开更多
Stable low-frequency squeezed vacuum states at a wavelength of 1550 nm were generated.By controlling the squeezing angle of the squeezed vacuum states,two types of low-frequency quadrature-phase squeezed vacuum states...Stable low-frequency squeezed vacuum states at a wavelength of 1550 nm were generated.By controlling the squeezing angle of the squeezed vacuum states,two types of low-frequency quadrature-phase squeezed vacuum states and quadrature-amplitude squeezed vacuum states were obtained using one setup respectively.A quantum-enhanced fiber Mach–Zehnder interferometer(FMZI)was demonstrated for low-frequency phase measurement using the generated quadrature-phase squeezed vacuum states that were injected.When phase modulation was measured with the quantumenhanced FMZI,there were above 3 dB quantum improvements beyond the shot-noise limit(SNL)from 40 kHz to 200 kHz,and 2.3 dB quantum improvement beyond the SNL at 20 kHz was obtained.The generated quadrature-amplitude squeezed vacuum state was applied to perform low-frequency amplitude modulation measurement for sensitivity beyond the SNL based on optical fiber construction.There were about 2 dB quantum improvements beyond the SNL from 60 kHz to 200 kHz.The current scheme proves that quantum-enhanced fiber-based sensors are feasible and have potential applications in high-precision measurements based on fiber,particularly in the low-frequency range.展开更多
For the beam splitter attack strategy against quantum key distribution using two-mode squeezed states, the analytical expression of the optimal beam splitter parameter is provided in this paper by applying the Shannon...For the beam splitter attack strategy against quantum key distribution using two-mode squeezed states, the analytical expression of the optimal beam splitter parameter is provided in this paper by applying the Shannon information theory. The theoretical secret information rate after error correction and privacy amplification is given in terms of the squeezed parameter and channel parameters. The results show that the two-mode squeezed state quantum key distribution is secure against an optimal beam splitter attack.展开更多
For the first time,we derive the compact forms of normalization factors for photon-added(-subtracted) two-mode squeezed thermal states by using the P-representation and the integration within an ordered product of o...For the first time,we derive the compact forms of normalization factors for photon-added(-subtracted) two-mode squeezed thermal states by using the P-representation and the integration within an ordered product of operators(IWOP) technique.It is found that these two factors are related to the Jacobi polynomials.In addition,some new relationships for Jacobi polynomials are presented.展开更多
Two new types of quantum states are constructed by applying the operator s(ξ) = exp(ξ* ab - ξa+b+) on the two-mode even and odd coherent states. The mathematical and quantum statistical properties of such st...Two new types of quantum states are constructed by applying the operator s(ξ) = exp(ξ* ab - ξa+b+) on the two-mode even and odd coherent states. The mathematical and quantum statistical properties of such states are investigated. Various nonclassical features of these states, such as squeezing properties, the inter-mode photon bunching, and the violation of Cauchy-Schwarz inequality, are discussed. The Wigner function in these states are studied in detail.展开更多
We explore how a two-mode squeezed vacuum state sechθeab tanh θ[00) evolves when it undergoes a single- mode amplitude dissipative channel with rate of decay k. We find that in this process not only the squeezing p...We explore how a two-mode squeezed vacuum state sechθeab tanh θ[00) evolves when it undergoes a single- mode amplitude dissipative channel with rate of decay k. We find that in this process not only the squeezing parameter decreases, tanhθ → e-kt tanh θ, but also the second-mode vacuum state evolves into a chaotic state exp{bbln[(1 - e-2kt) tanh2 θ]}. The outcome state is no more a pure state, but an entangled mixed state.展开更多
In this paper, the two-mode excited squeezed vacuum state (TESVS) is studied by using the statistical method. By calculating the normalization of the TESVS, a new form of Jacobi polynomials and some new identities a...In this paper, the two-mode excited squeezed vacuum state (TESVS) is studied by using the statistical method. By calculating the normalization of the TESVS, a new form of Jacobi polynomials and some new identities are obtained. The photon number distribution of the TESVS is given and it is a simple form of Jacobi polynomials. Using the entangled state representation of Wigner operator, the Wigner function of the TESVS is obtainded and the variations of the Wigner function with the parameters m, n, and r are discussed. Here from the phase space point of view the TESVS can be well interpreted and described.展开更多
We investigate the influence of the Stark shift on the entanglement transfer from the two-mode squeezed vacuum state field to two spatially separated atoms in two-photon processes. Our results show that the Stark shif...We investigate the influence of the Stark shift on the entanglement transfer from the two-mode squeezed vacuum state field to two spatially separated atoms in two-photon processes. Our results show that the Stark shift plays an important role in such entanglement transfer. We find that when the Stark shift parameter r is small, the degree of entanglement between the two atoms increases with the increasing of the squeezing parameter ξ first, and after achieving its maximal value, the degree of entanglement will decrease to zero with the increasing of ξ; while for big r, E will increase with the increasing of ξ.展开更多
The result of one-mode quadrature-amplitude measurement for some generalized two-mode squeezed states has been studied by virtue of the entangled state representation of the corresponding two-mode squeezing operators....The result of one-mode quadrature-amplitude measurement for some generalized two-mode squeezed states has been studied by virtue of the entangled state representation of the corresponding two-mode squeezing operators. We find that the remaining fleld-mode simultaneously collapses to the single-mode squeezed state with more stronger squeezing. The measurement result caused by a single-mode squeezed state projector is also calculated, which indicates quantum entanglement in squeezing.展开更多
Entanglement properties of two-mode squeezed coherent states in the radiation field &re investigated according to the entanglement criterion [Phys. Rev. Lett. 84 (2000) 2722]. The dependence of entanglement on sque...Entanglement properties of two-mode squeezed coherent states in the radiation field &re investigated according to the entanglement criterion [Phys. Rev. Lett. 84 (2000) 2722]. The dependence of entanglement on squeeze angle and squeeze parameter is discussed. It shows that the system evolves into entangled states and entanglement does not increase persistently with the increase of squeeze angle and squeeze parameter. There only exists a certain squeeze angle in which the entanglement exists continuously.展开更多
We investigate photon statistical properties of the multiple-photon-added two-mode squeezed coherent states (PA- TMSCS). We find that the photon statistical properties are sensitive to the compound phase involved in...We investigate photon statistical properties of the multiple-photon-added two-mode squeezed coherent states (PA- TMSCS). We find that the photon statistical properties are sensitive to the compound phase involved in the TMSCS. Our numerical analyses show that the photon addition can enhance the cross-correlation and anti-bunching effects of the PA- TMSCS. Compared with that of the TMSCS, the photon number distribution of the PA-TMSCS is modulated by a factor that is a monotonically increasing function of the numbers of adding photons to each mode; further, that the photon addition essentially shifts the photon number distribution.展开更多
The q-analogues of two-mode squeezed states are introduced by virtue of deformation quantization methods and the technique of integration within an ordered product (IWOP) of operators. Some new completeness relation...The q-analogues of two-mode squeezed states are introduced by virtue of deformation quantization methods and the technique of integration within an ordered product (IWOP) of operators. Some new completeness relations about these squeezed states composed of the bra and ket which are not mutually Hermitian conjugates are obtained. Furthermore, the antibunching effects of the two-mode squeezed vacuum state S's(τ) │00) are investigated. It is found that, in different ranges of the squeezed parameter τ, both modes of the state exhibit the antibunching effects and the two modes of the state are always nonclassical correlation.展开更多
The system of the Hamiltonian involving a driving part,a single mode part,and a two-mode squeezedone and a two-mode coupled one is discussed using the Lewis-Riesenfeld invariant theory.The time evolution operatoris ob...The system of the Hamiltonian involving a driving part,a single mode part,and a two-mode squeezedone and a two-mode coupled one is discussed using the Lewis-Riesenfeld invariant theory.The time evolution operatoris obtained.When the initial state is a coherent state,the quantum fluctuation of the system is calculated,and it isdependent on the squeezed part and the two-mode coupled part,but not dependent on the driving one.展开更多
For the first time, we derive the photon number cumulant for two-mode squeezed state and show that its cumulant expansion leads to normalization of two-mode photon subtracted-squeezed states and photon added- squeezed...For the first time, we derive the photon number cumulant for two-mode squeezed state and show that its cumulant expansion leads to normalization of two-mode photon subtracted-squeezed states and photon added- squeezed states. We show that the normalization is related to Jacobi polynomial, so the cumulant expansion in turn represents the new generating function of Jacobi polynomial.展开更多
We introduce the coordinate-dependent one-and two-mode squeezing transformations and discuss theproperties of the corresponding one-and two-mode squeezed states.We show that the coordinate-dependent one-and two-mode s...We introduce the coordinate-dependent one-and two-mode squeezing transformations and discuss theproperties of the corresponding one-and two-mode squeezed states.We show that the coordinate-dependent one-and two-mode squeezing transformations can be constructed by the combination of two transformations,a coordinate-dependentdisplacement followed by the standard squeezed transformation.Such a decomposition turns a nonlinear problem intoa linear one because all the calculations involving the nonlinear one- and two-mode squeezed transformation have beenshown to be able to reduce to those only concerning the standard one- and two-mode squeezed states.展开更多
In this paper, we introduce photon-added and photon-subtracted squeezed vacuum state (PASV and PSSV) and obtain their normalized factors, which have the similar forms involved in Lengendre polynomials. Moreover, we ...In this paper, we introduce photon-added and photon-subtracted squeezed vacuum state (PASV and PSSV) and obtain their normalized factors, which have the similar forms involved in Lengendre polynomials. Moreover, we give the compact expressions of Wigner function, which are related to single-variable Hermite polynomials. Especially, we compare their nonclassicality in terms of Mandel Q-factor and the negativity of Wigner function.展开更多
We propose an arbitrated quantum signature (AQS) scheme with continuous variable (CV) squeezed vacuum states, which requires three parties, i.e., the signer Alice, the verifier Bob and the arbitrator Charlie trust...We propose an arbitrated quantum signature (AQS) scheme with continuous variable (CV) squeezed vacuum states, which requires three parties, i.e., the signer Alice, the verifier Bob and the arbitrator Charlie trusted by Alice and Bob, and three phases consisting of the initial phase, the signature phase and the verification phase. We evaluate and compare the original state and the teleported state by using the fidelity and the beam splitter (BS) strategy. The security is ensured by the CV-based quantum key distribution (CV-QKD) and quantum teleportation of squeezed states. Security analyses show that the generated signature can be neither disavowed by the signer and the receiver nor counterfeited by anyone with the shared keys. Furthermore, the scheme can also detect other manners of potential attack although they may be successful. Also, the integrality and authenticity of the transmitted messages can be guaranteed. Compared to the signature scheme of CV-based coherent states, our scheme has better encoding efficiency and performance. It is a potential high-speed quantum signature scheme with high repetition rate and detection efficiency which can be achieved by using the standard off-the-shelf components when compared to the discrete-variable (DV) quantum signature scheme.展开更多
By applying the bosonic creation operator to squeezed vacuum states, this paper introduces a new kind of quantum states: photon-added squeezed vacuum states. It also presents an experimental approach to prepare these...By applying the bosonic creation operator to squeezed vacuum states, this paper introduces a new kind of quantum states: photon-added squeezed vacuum states. It also presents an experimental approach to prepare these states, and investigates their quantum statistical properties by the numerical method. The results indicate that these states reveal some interesting non-classical properties, such as anti-bunching effects, squeezing effects and negativities of the relevant Wigner functions.展开更多
This paper presents a realistic scheme for the teleportation of coherent states in which a two-mode squeezed vacuum state serves as the quantum channel and the position-sum and momentum-difference of two local modes s...This paper presents a realistic scheme for the teleportation of coherent states in which a two-mode squeezed vacuum state serves as the quantum channel and the position-sum and momentum-difference of two local modes serve as the measuring observables. The average fidelity of the teleportation of coherent states is derived for finite squeezing parameters and it turns out that fidelity greater than 1/2 cannot be achieved by using a classical channel alone and the probability distribution of the measurement result is a Gaussian distribution around the unknown parameter of the input coherent state with a width given by the squeezing parameter.展开更多
基金Supported by the National Natural Science Foundation of China under Grant No.10574060Shandong Province of China under Grant No.Y2008A23Liaocheng University of China under Grant No.X071049
文摘In this paper,two-mode displaced excited squeezed vacuum states (TDESVS) are constructed and theirnormalization and completeness are investigated.Using the entangled state representation and Weyl ordering formof the Wigner operator,the Wigner functions of TDESVS are obtained and the variations of Wigner functions withthe parameters m,n and r are investigated.Besides,two marginal distributions of Wigner functions of TDESVS areobtained,which exhibit some entangled properties of the two-particle's system in TDESVS.
基金Project supported by the National Natural Science Foundation of China(Grant No.62175135)the Fundamental Research Program of Shanxi Province(Grant No.202103021224025)。
文摘Stable low-frequency squeezed vacuum states at a wavelength of 1550 nm were generated.By controlling the squeezing angle of the squeezed vacuum states,two types of low-frequency quadrature-phase squeezed vacuum states and quadrature-amplitude squeezed vacuum states were obtained using one setup respectively.A quantum-enhanced fiber Mach–Zehnder interferometer(FMZI)was demonstrated for low-frequency phase measurement using the generated quadrature-phase squeezed vacuum states that were injected.When phase modulation was measured with the quantumenhanced FMZI,there were above 3 dB quantum improvements beyond the shot-noise limit(SNL)from 40 kHz to 200 kHz,and 2.3 dB quantum improvement beyond the SNL at 20 kHz was obtained.The generated quadrature-amplitude squeezed vacuum state was applied to perform low-frequency amplitude modulation measurement for sensitivity beyond the SNL based on optical fiber construction.There were about 2 dB quantum improvements beyond the SNL from 60 kHz to 200 kHz.The current scheme proves that quantum-enhanced fiber-based sensors are feasible and have potential applications in high-precision measurements based on fiber,particularly in the low-frequency range.
基金Project supported by the Shanghai Jiaotong University (SJTU) Young Teacher Foundation,China (Grant No A2831B)the SJTU Participating in Research Projects (PRPs),China (Grant No T03011030)the National Natural Science Foundation of China(Grant No 60472018)
文摘For the beam splitter attack strategy against quantum key distribution using two-mode squeezed states, the analytical expression of the optimal beam splitter parameter is provided in this paper by applying the Shannon information theory. The theoretical secret information rate after error correction and privacy amplification is given in terms of the squeezed parameter and channel parameters. The results show that the two-mode squeezed state quantum key distribution is secure against an optimal beam splitter attack.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 11264018 and 60978009)the Major Research Plan of the National Natural Science Foundation of China (Grant No. 91121023)+1 种基金the National Basic Research Project of China (Grant No. 2011CBA00200)the Young Talents Foundation of Jiangxi Normal University,China
文摘For the first time,we derive the compact forms of normalization factors for photon-added(-subtracted) two-mode squeezed thermal states by using the P-representation and the integration within an ordered product of operators(IWOP) technique.It is found that these two factors are related to the Jacobi polynomials.In addition,some new relationships for Jacobi polynomials are presented.
基金The project supported by National Natural Science Foundation of China under Grant No. 10472040, Science Foundation of the Education Department of Liaoning Province under Grant No. 05L151
文摘Two new types of quantum states are constructed by applying the operator s(ξ) = exp(ξ* ab - ξa+b+) on the two-mode even and odd coherent states. The mathematical and quantum statistical properties of such states are investigated. Various nonclassical features of these states, such as squeezing properties, the inter-mode photon bunching, and the violation of Cauchy-Schwarz inequality, are discussed. The Wigner function in these states are studied in detail.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 11047133 and 10647133)the Natural Science Foundation of Jiangxi Province of China (Grant Nos. 2009GQS0080 and 2010GQW0027)the Research Foundation of the Education Department of Jiangxi Province of China (Grant Nos. GJJ11339 and GJJ10097)
文摘We explore how a two-mode squeezed vacuum state sechθeab tanh θ[00) evolves when it undergoes a single- mode amplitude dissipative channel with rate of decay k. We find that in this process not only the squeezing parameter decreases, tanhθ → e-kt tanh θ, but also the second-mode vacuum state evolves into a chaotic state exp{bbln[(1 - e-2kt) tanh2 θ]}. The outcome state is no more a pure state, but an entangled mixed state.
基金The project supported by National Natural Science Foundation of China under Grant No.10574060the Natural Science Foundation of Shandong Province of China under Grant No.Y2004A09
文摘In this paper, the two-mode excited squeezed vacuum state (TESVS) is studied by using the statistical method. By calculating the normalization of the TESVS, a new form of Jacobi polynomials and some new identities are obtained. The photon number distribution of the TESVS is given and it is a simple form of Jacobi polynomials. Using the entangled state representation of Wigner operator, the Wigner function of the TESVS is obtainded and the variations of the Wigner function with the parameters m, n, and r are discussed. Here from the phase space point of view the TESVS can be well interpreted and described.
基金The project supported by National Natural Science Foundation of China under Grant No.10374007
文摘We investigate the influence of the Stark shift on the entanglement transfer from the two-mode squeezed vacuum state field to two spatially separated atoms in two-photon processes. Our results show that the Stark shift plays an important role in such entanglement transfer. We find that when the Stark shift parameter r is small, the degree of entanglement between the two atoms increases with the increasing of the squeezing parameter ξ first, and after achieving its maximal value, the degree of entanglement will decrease to zero with the increasing of ξ; while for big r, E will increase with the increasing of ξ.
文摘The result of one-mode quadrature-amplitude measurement for some generalized two-mode squeezed states has been studied by virtue of the entangled state representation of the corresponding two-mode squeezing operators. We find that the remaining fleld-mode simultaneously collapses to the single-mode squeezed state with more stronger squeezing. The measurement result caused by a single-mode squeezed state projector is also calculated, which indicates quantum entanglement in squeezing.
基金The project supported by National Natural Science Foundation of China under Grant Nos.10174024 and 10474025
文摘Entanglement properties of two-mode squeezed coherent states in the radiation field &re investigated according to the entanglement criterion [Phys. Rev. Lett. 84 (2000) 2722]. The dependence of entanglement on squeeze angle and squeeze parameter is discussed. It shows that the system evolves into entangled states and entanglement does not increase persistently with the increase of squeeze angle and squeeze parameter. There only exists a certain squeeze angle in which the entanglement exists continuously.
基金Project supported by the National Natural Science Foundation of China (Grant Nos.11174114 and 61107055)the Natural Science Foundation of Wuxi Institute of Technology of China (Grant No.401301293)
文摘We investigate photon statistical properties of the multiple-photon-added two-mode squeezed coherent states (PA- TMSCS). We find that the photon statistical properties are sensitive to the compound phase involved in the TMSCS. Our numerical analyses show that the photon addition can enhance the cross-correlation and anti-bunching effects of the PA- TMSCS. Compared with that of the TMSCS, the photon number distribution of the PA-TMSCS is modulated by a factor that is a monotonically increasing function of the numbers of adding photons to each mode; further, that the photon addition essentially shifts the photon number distribution.
基金Project supported by the National Natural Science Foundation of China (Grant No 10574060)the Natural Science Foundation of Liaocheng University of China (Grant No X071049)
文摘The q-analogues of two-mode squeezed states are introduced by virtue of deformation quantization methods and the technique of integration within an ordered product (IWOP) of operators. Some new completeness relations about these squeezed states composed of the bra and ket which are not mutually Hermitian conjugates are obtained. Furthermore, the antibunching effects of the two-mode squeezed vacuum state S's(τ) │00) are investigated. It is found that, in different ranges of the squeezed parameter τ, both modes of the state exhibit the antibunching effects and the two modes of the state are always nonclassical correlation.
基金National Natural Science Foundation of China under Grant Nos.10405006 and 10547106
文摘The system of the Hamiltonian involving a driving part,a single mode part,and a two-mode squeezedone and a two-mode coupled one is discussed using the Lewis-Riesenfeld invariant theory.The time evolution operatoris obtained.When the initial state is a coherent state,the quantum fluctuation of the system is calculated,and it isdependent on the squeezed part and the two-mode coupled part,but not dependent on the driving one.
基金Project supported by the Natural Science Foundation of Fujian Province,China (Grant No.2011J01018)the National Natural Science Foundation of China (Grant No.11175113)
文摘For the first time, we derive the photon number cumulant for two-mode squeezed state and show that its cumulant expansion leads to normalization of two-mode photon subtracted-squeezed states and photon added- squeezed states. We show that the normalization is related to Jacobi polynomial, so the cumulant expansion in turn represents the new generating function of Jacobi polynomial.
文摘We introduce the coordinate-dependent one-and two-mode squeezing transformations and discuss theproperties of the corresponding one-and two-mode squeezed states.We show that the coordinate-dependent one-and two-mode squeezing transformations can be constructed by the combination of two transformations,a coordinate-dependentdisplacement followed by the standard squeezed transformation.Such a decomposition turns a nonlinear problem intoa linear one because all the calculations involving the nonlinear one- and two-mode squeezed transformation have beenshown to be able to reduce to those only concerning the standard one- and two-mode squeezed states.
基金supported by the National Natural Science Foundation of China (Grant No.11047133)the Natural Science Foundation of Jiangxi Province of China (Grant No.2010GQW0027)+1 种基金the Key Program Foundation of Ministry of Education of China (Grant No.210115)the Research Foundation of the Education Department of Jiangxi Province of China (Grant Nos.GJJ10097 and GJJ11390)
文摘In this paper, we introduce photon-added and photon-subtracted squeezed vacuum state (PASV and PSSV) and obtain their normalized factors, which have the similar forms involved in Lengendre polynomials. Moreover, we give the compact expressions of Wigner function, which are related to single-variable Hermite polynomials. Especially, we compare their nonclassicality in terms of Mandel Q-factor and the negativity of Wigner function.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61379153 and 61572529)
文摘We propose an arbitrated quantum signature (AQS) scheme with continuous variable (CV) squeezed vacuum states, which requires three parties, i.e., the signer Alice, the verifier Bob and the arbitrator Charlie trusted by Alice and Bob, and three phases consisting of the initial phase, the signature phase and the verification phase. We evaluate and compare the original state and the teleported state by using the fidelity and the beam splitter (BS) strategy. The security is ensured by the CV-based quantum key distribution (CV-QKD) and quantum teleportation of squeezed states. Security analyses show that the generated signature can be neither disavowed by the signer and the receiver nor counterfeited by anyone with the shared keys. Furthermore, the scheme can also detect other manners of potential attack although they may be successful. Also, the integrality and authenticity of the transmitted messages can be guaranteed. Compared to the signature scheme of CV-based coherent states, our scheme has better encoding efficiency and performance. It is a potential high-speed quantum signature scheme with high repetition rate and detection efficiency which can be achieved by using the standard off-the-shelf components when compared to the discrete-variable (DV) quantum signature scheme.
基金Project supported by the National Natural Science Foundation of China (Grant No.10874142)
文摘By applying the bosonic creation operator to squeezed vacuum states, this paper introduces a new kind of quantum states: photon-added squeezed vacuum states. It also presents an experimental approach to prepare these states, and investigates their quantum statistical properties by the numerical method. The results indicate that these states reveal some interesting non-classical properties, such as anti-bunching effects, squeezing effects and negativities of the relevant Wigner functions.
基金Project supported by the National Natural Science Foundation of China (Grant No 20477043).
文摘This paper presents a realistic scheme for the teleportation of coherent states in which a two-mode squeezed vacuum state serves as the quantum channel and the position-sum and momentum-difference of two local modes serve as the measuring observables. The average fidelity of the teleportation of coherent states is derived for finite squeezing parameters and it turns out that fidelity greater than 1/2 cannot be achieved by using a classical channel alone and the probability distribution of the measurement result is a Gaussian distribution around the unknown parameter of the input coherent state with a width given by the squeezing parameter.