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
A new kind of non-Gaussian quantum catalyzed state is proposed via multiphoton measurements and two-mode squeezing as an input of thermal state.The characteristics of the generated multiphoton catalysis output state d...A new kind of non-Gaussian quantum catalyzed state is proposed via multiphoton measurements and two-mode squeezing as an input of thermal state.The characteristics of the generated multiphoton catalysis output state depends on the thermal parameter,catalyzed photon number and squeezing parameter.We then analyze the nonclassical properties by examining the photon number distribution,photocount distribution and partial negativity of the Wigner function.Our findings indicate that nonclassicality can be achieved through the implementation of multiphoton catalysis operations and modulated by the thermal parameter,catalyzed photon number and squeezing parameter.展开更多
We investigate the nonclassical properties of arbitrary number photon annihilation-then-creation operation （AC） and creation-then-annihilation operation （CA） to the thermal state （TS）, whose normalization factor...We investigate the nonclassical properties of arbitrary number photon annihilation-then-creation operation （AC） and creation-then-annihilation operation （CA） to the thermal state （TS）, whose normalization factors are related to the polylog- arithm function. Then we compare their quantum characters, such as photon number distribution, average photon number, Mandel Q-parameter, purity and the Wigner function. Because of the noncommutativity between the annihilation operator and the creation operator, the ACTS and the CATS have different nonclassical properties. It is found that nonclassical properties are exhibited more strongly after AC than after CA. In addition we also examine their non-Gaussianity. The result shows that the ACTS can present a slightly bigger non-Gaussianity than the CATS.展开更多
We theoretically analyze the nonclassicality and entanglement of two new non-Gaussian entangled states generated by applying multiple-photon addition and subtraction to a two-mode binomial state.The nonclassical prope...We theoretically analyze the nonclassicality and entanglement of two new non-Gaussian entangled states generated by applying multiple-photon addition and subtraction to a two-mode binomial state.The nonclassical properties are investigated in terms of the partial negativity of the Wigner functions,whose results show that their nonclassicality can be enhanced via one-mode even-number photon operations and two-mode symmetrical operations for the initial two-mode binomial state.We also find that there exists some enhancement in the entanglement properties in certain parameter ranges via one-mode photon-addition and two-mode symmetrical operations.展开更多
The nonclassicality of the two-variable Hermite polynomial state is investigated. It is found that the two-variable Hermite polynomial state can be considered as a two-mode photon subtracted squeezed vacuum state. A c...The nonclassicality of the two-variable Hermite polynomial state is investigated. It is found that the two-variable Hermite polynomial state can be considered as a two-mode photon subtracted squeezed vacuum state. A compact expression for the Wigner function is also derived analytically by using the Weyl-ordered operator invariance under similar transformations. Especially, the nonclassicality is discussed in terms of the negativity of the Wigner function. Then violations of Bell＇s inequality for the two-variable Hermite polynomial state are studied.展开更多
Nonclassicality is an essential but still open question in quantum mechanics. Here, utilizing the maximum value of quantum Fisher information, we suggest a new version of the nonclassical criterion for SU(2) generator...Nonclassicality is an essential but still open question in quantum mechanics. Here, utilizing the maximum value of quantum Fisher information, we suggest a new version of the nonclassical criterion for SU(2) generator realized by two bosonic modes. As an application of the criterion, the system of two coupled nonlinear nanomechanical resonators is considered. And the nonclassicality of the phonon state in the dynamical evolution is explored. The system has a dynamical phase transition from the tunnelling phase to the self-trapping phase by tuning the coupling strength. It is found that for the tunnelling phase, the phonon state is nonclassical in the full time evolution. And for the self-trapping phase, the evolved phonon state is still nonclassical in the full time with a relatively large coupling strength, while it is nonclassical i n the most of time (but not all) with a small coupling strength. Quantum coherence has distinct different behaviors in the two phases.展开更多
Considering two light beams which are in general single-mode Gaussian states and incident on input ports of an ideal beam splitter, respectively, this paper investigates how separability and entanglement of the output...Considering two light beams which are in general single-mode Gaussian states and incident on input ports of an ideal beam splitter, respectively, this paper investigates how separability and entanglement of the output lights depend on degrees of nonclassicality and purities of the input states. The minimum and maximum amounts of attainable entanglement in the output state are found展开更多
The statistical properties of m-coherent superposition operation（μa ＋ νa）^m on the single-mode squeezed vacuum state（M-SSVS） and its decoherence in a thermal environment are studied.Converting the M-SSVS to a s...The statistical properties of m-coherent superposition operation（μa ＋ νa）^m on the single-mode squeezed vacuum state（M-SSVS） and its decoherence in a thermal environment are studied.Converting the M-SSVS to a squeezed Hermite polynomial excitation state,we obtain a compact expression for the normalization factor of M-SSVS,which is the Legendre polynomial of the squeezing parameter.We also derive the explicit expression of the Wigner function（WF） of the M-SSVS,and find the negative region of the WF in phase space.The decoherence effect on this state is then discussed by deriving the time evolution of the WF.Using the negativity of the WF,the loss of nonclassicality is then discussed.展开更多
After developing the mathematical means for the correspondence of classical phase-space function to quantum-mechanical operators with symmetrical ordering of the basic canonical operators in the sense of Weyl the appr...After developing the mathematical means for the correspondence of classical phase-space function to quantum-mechanical operators with symmetrical ordering of the basic canonical operators in the sense of Weyl the approach is applied to an infinite series of classical monomial functions of the canonical variables. These include as well as pure powers of the amplitude as also basic periodic functions of the phase φwith their quantum-mechanical correspondence. In the representation by number states, all the considered operators involve the Jacobi polynomials as the essential formative element. Whereas the quantity in normal ordering due to its indeterminacy leads to the introduction of the notions of sub- and super-Poissonian statistics the analogous quantity in (Weyl) symmetrical orderingis positive definite and satisfies an inequality. The notions of sub- and super-Poissonian statistics are problematic when they are used for the definition of nonclassicality of states since the mentioned measure in normal ordering does not determine the Poisson statistics in their middle in unique way but determines only a large set of statistics which may be very far in the sense of the Hilbert-Schmidt distance from a Poisson statistics that is discussed.展开更多
Nonclassical states play a crucial role in both theoretical and experimental investigations of quantum optics, and there is a wide interest in characterization and quantification of nonclassicality. By exploiting the ...Nonclassical states play a crucial role in both theoretical and experimental investigations of quantum optics, and there is a wide interest in characterization and quantification of nonclassicality. By exploiting the freedom of the parameter s in the s-ordered phase-space distribution introduced by Cahill and Glauber [Phys. Rev. 177, 1882(1969)], we develop a method to reveal and quantify optical nonclassicality via the divided difference of the s-ordered phase-space distribution. Our approach yields naturally a family of quantifiers of optical nonclassicality, which have many desirable properties such as convexity and monotonicity under the Gaussian noise channels. The quantifiers are illustrated by evaluating nonclassicality of several typical states. Two simple and convenient criteria for nonclassicality are established, which in particular certify all nonclassical Gaussian states.展开更多
Two new photon-modulated spin coherent states(SCSs)are introduced by operating the spin ladder operators J±on the ordinary SCS in the Holstein-Primakoff realization and the nonclassicality is exhibited via their ...Two new photon-modulated spin coherent states(SCSs)are introduced by operating the spin ladder operators J±on the ordinary SCS in the Holstein-Primakoff realization and the nonclassicality is exhibited via their photon number distribution,second-order correlation function,photocount distribution and negativity of Wigner distribution.Analytical results show that the photocount distribution is a Bernoulli distribution and the Wigner functions are only associated with two-variable Hermite polynomials.Compared with the ordinary SCS,the photon-modulated SCSs exhibit more stronger nonclassicality in certain regions of the photon modulated number k and spin number j,which means that the nonclassicality can be enhanced by selecting suitable parameters.展开更多
We theoretically introduce two new photon-modulated atomic coherent states(ACSs)via using the Schwinger bosonic representation of the angular momentum operators(the sequential operations J±n)on an ACS,and investi...We theoretically introduce two new photon-modulated atomic coherent states(ACSs)via using the Schwinger bosonic representation of the angular momentum operators(the sequential operations J±n)on an ACS,and investigate their nonclassicality using the Wigner distribution,photon number distribution,and entanglement entropy.It is found that photonmodulated ACSs possess more stronger nonclassicality than the original ACS in certain regions ofτ,the nonclassicality enhances with increasing number n of the operations J±and the operation J+(-)n enhances the entanglement in the region of small(large)τ.展开更多
We quantify the nonclassicality of multimode bosonic field states by adopting an information-theoretic approach involving the Wigner-Yanase skew information.The fundamental properties of the quantifier such as convexi...We quantify the nonclassicality of multimode bosonic field states by adopting an information-theoretic approach involving the Wigner-Yanase skew information.The fundamental properties of the quantifier such as convexity,superadditivity,monotonicity,and conservation relations are revealed.The quantifier is illustrated by a variety of typical examples,and applications to the quantification of nonclassical correlations are discussed.Various extensions are indicated.展开更多
We prove the existence of global attractors in H0^1 （Ω） for a nonclassical diffusion equation. Two types of nonlinearity f are considered： one is the critical exponent, and the other is the polynomial growth of ar...We prove the existence of global attractors in H0^1 （Ω） for a nonclassical diffusion equation. Two types of nonlinearity f are considered： one is the critical exponent, and the other is the polynomial growth of arbitrary order.展开更多
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supported by the National Natural Science Foundation of China (Grant No.11347026)the Natural Science Foundation of Shandong Province,China (Grant Nos.ZR2020MA085 and ZR2020MF113)。
文摘A new kind of non-Gaussian quantum catalyzed state is proposed via multiphoton measurements and two-mode squeezing as an input of thermal state.The characteristics of the generated multiphoton catalysis output state depends on the thermal parameter,catalyzed photon number and squeezing parameter.We then analyze the nonclassical properties by examining the photon number distribution,photocount distribution and partial negativity of the Wigner function.Our findings indicate that nonclassicality can be achieved through the implementation of multiphoton catalysis operations and modulated by the thermal parameter,catalyzed photon number and squeezing parameter.
基金supported by the National Natural Science Foundation of China(Grant Nos.11264018 and 11174114)the Research Foundation of the Education Department of Jiangxi Province of China(Grant Nos.GJJ12171 and GJJ12202)+2 种基金the Science Fund for Youth of Jiangxi Province,China(GrantNos.20132BAB212006 and 2011ZBAB215036)the Open Foundation of the Key Laboratory of Optoelectronic and Telecommunication of Jiangxi Province,China(Grant No.2013004)the National Science Foundation of Jiangsu Higher Education Institute of China(Grant No.12KJD140001)
文摘We investigate the nonclassical properties of arbitrary number photon annihilation-then-creation operation （AC） and creation-then-annihilation operation （CA） to the thermal state （TS）, whose normalization factors are related to the polylog- arithm function. Then we compare their quantum characters, such as photon number distribution, average photon number, Mandel Q-parameter, purity and the Wigner function. Because of the noncommutativity between the annihilation operator and the creation operator, the ACTS and the CATS have different nonclassical properties. It is found that nonclassical properties are exhibited more strongly after AC than after CA. In addition we also examine their non-Gaussianity. The result shows that the ACTS can present a slightly bigger non-Gaussianity than the CATS.
基金Supported by the National Natural Science Foundation of China under Grant No.11347026the Natural Science Foundation of Shandong Province under Grant Nos.ZR2016AM03 and ZR2017MA011
文摘We theoretically analyze the nonclassicality and entanglement of two new non-Gaussian entangled states generated by applying multiple-photon addition and subtraction to a two-mode binomial state.The nonclassical properties are investigated in terms of the partial negativity of the Wigner functions,whose results show that their nonclassicality can be enhanced via one-mode even-number photon operations and two-mode symmetrical operations for the initial two-mode binomial state.We also find that there exists some enhancement in the entanglement properties in certain parameter ranges via one-mode photon-addition and two-mode symmetrical operations.
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)the Research Foundation of the Education Department of Jiangxi Province of China (Grant No. GJJ11390)
文摘The nonclassicality of the two-variable Hermite polynomial state is investigated. It is found that the two-variable Hermite polynomial state can be considered as a two-mode photon subtracted squeezed vacuum state. A compact expression for the Wigner function is also derived analytically by using the Weyl-ordered operator invariance under similar transformations. Especially, the nonclassicality is discussed in terms of the negativity of the Wigner function. Then violations of Bell＇s inequality for the two-variable Hermite polynomial state are studied.
基金Supported by the National Natural Science Foundation of China under Grant No.11365006the Natural Science Foundation of Guizhou Province under Grant No.QKHLHZ[2015]7767
文摘Nonclassicality is an essential but still open question in quantum mechanics. Here, utilizing the maximum value of quantum Fisher information, we suggest a new version of the nonclassical criterion for SU(2) generator realized by two bosonic modes. As an application of the criterion, the system of two coupled nonlinear nanomechanical resonators is considered. And the nonclassicality of the phonon state in the dynamical evolution is explored. The system has a dynamical phase transition from the tunnelling phase to the self-trapping phase by tuning the coupling strength. It is found that for the tunnelling phase, the phonon state is nonclassical in the full time evolution. And for the self-trapping phase, the evolved phonon state is still nonclassical in the full time with a relatively large coupling strength, while it is nonclassical i n the most of time (but not all) with a small coupling strength. Quantum coherence has distinct different behaviors in the two phases.
基金Project supported by the National Natural Science Foundation of China （Grant No 10574103）.
文摘Considering two light beams which are in general single-mode Gaussian states and incident on input ports of an ideal beam splitter, respectively, this paper investigates how separability and entanglement of the output lights depend on degrees of nonclassicality and purities of the input states. The minimum and maximum amounts of attainable entanglement in the output state are found
基金Project supported by the National Natural Science Foundation of China (Grant No. 11047133)the Natural Science Foundation of Jiangxi Province,China (Grant Nos. 20114BAB202004 and 2009GZW0006)the Research Foundation of the Education Department of Jiangxi Province,China (GrantNo. GJJ11390)
文摘The statistical properties of m-coherent superposition operation（μa ＋ νa）^m on the single-mode squeezed vacuum state（M-SSVS） and its decoherence in a thermal environment are studied.Converting the M-SSVS to a squeezed Hermite polynomial excitation state,we obtain a compact expression for the normalization factor of M-SSVS,which is the Legendre polynomial of the squeezing parameter.We also derive the explicit expression of the Wigner function（WF） of the M-SSVS,and find the negative region of the WF in phase space.The decoherence effect on this state is then discussed by deriving the time evolution of the WF.Using the negativity of the WF,the loss of nonclassicality is then discussed.
文摘After developing the mathematical means for the correspondence of classical phase-space function to quantum-mechanical operators with symmetrical ordering of the basic canonical operators in the sense of Weyl the approach is applied to an infinite series of classical monomial functions of the canonical variables. These include as well as pure powers of the amplitude as also basic periodic functions of the phase φwith their quantum-mechanical correspondence. In the representation by number states, all the considered operators involve the Jacobi polynomials as the essential formative element. Whereas the quantity in normal ordering due to its indeterminacy leads to the introduction of the notions of sub- and super-Poissonian statistics the analogous quantity in (Weyl) symmetrical orderingis positive definite and satisfies an inequality. The notions of sub- and super-Poissonian statistics are problematic when they are used for the definition of nonclassicality of states since the mentioned measure in normal ordering does not determine the Poisson statistics in their middle in unique way but determines only a large set of statistics which may be very far in the sense of the Hilbert-Schmidt distance from a Poisson statistics that is discussed.
基金supported by the National Natural Science Foundation of China(Grant Nos.11975026,and 12125402)National Key R&D Program of China(Grant No.2020YFA0712700)+2 种基金China Postdoctoral Science Foundation(Grant No.2021M690414)Beijing Postdoctoral Research Foundation(Grant No.2021ZZ091)Beijing Natural Science Foundation(Grant No.Z190005)。
文摘Nonclassical states play a crucial role in both theoretical and experimental investigations of quantum optics, and there is a wide interest in characterization and quantification of nonclassicality. By exploiting the freedom of the parameter s in the s-ordered phase-space distribution introduced by Cahill and Glauber [Phys. Rev. 177, 1882(1969)], we develop a method to reveal and quantify optical nonclassicality via the divided difference of the s-ordered phase-space distribution. Our approach yields naturally a family of quantifiers of optical nonclassicality, which have many desirable properties such as convexity and monotonicity under the Gaussian noise channels. The quantifiers are illustrated by evaluating nonclassicality of several typical states. Two simple and convenient criteria for nonclassicality are established, which in particular certify all nonclassical Gaussian states.
基金supported by the National Natural Science Foundation of China(Grant No.11347026)the Natural Science Foundation of Shandong Province,China(Grant Nos.ZR2020MA085 and ZR2020MF113)。
文摘Two new photon-modulated spin coherent states(SCSs)are introduced by operating the spin ladder operators J±on the ordinary SCS in the Holstein-Primakoff realization and the nonclassicality is exhibited via their photon number distribution,second-order correlation function,photocount distribution and negativity of Wigner distribution.Analytical results show that the photocount distribution is a Bernoulli distribution and the Wigner functions are only associated with two-variable Hermite polynomials.Compared with the ordinary SCS,the photon-modulated SCSs exhibit more stronger nonclassicality in certain regions of the photon modulated number k and spin number j,which means that the nonclassicality can be enhanced by selecting suitable parameters.
基金Project supported by the National Natural Science Foundation of China(Grant No.11347026)the Natural Science Foundation of Shandong Province,China(Grant Nos.ZR2016AM03 and ZR2017MA011)。
文摘We theoretically introduce two new photon-modulated atomic coherent states(ACSs)via using the Schwinger bosonic representation of the angular momentum operators(the sequential operations J±n)on an ACS,and investigate their nonclassicality using the Wigner distribution,photon number distribution,and entanglement entropy.It is found that photonmodulated ACSs possess more stronger nonclassicality than the original ACS in certain regions ofτ,the nonclassicality enhances with increasing number n of the operations J±and the operation J+(-)n enhances the entanglement in the region of small(large)τ.
基金supported by the National Key R&D Program of China,Grant No.2020YFA0712700the National Natural Science Foundation of China,Grant Nos.11875317and 61833010。
文摘We quantify the nonclassicality of multimode bosonic field states by adopting an information-theoretic approach involving the Wigner-Yanase skew information.The fundamental properties of the quantifier such as convexity,superadditivity,monotonicity,and conservation relations are revealed.The quantifier is illustrated by a variety of typical examples,and applications to the quantification of nonclassical correlations are discussed.Various extensions are indicated.
基金Supported in part by the NSFC,Grant(10471056)Trans-Century Training Programme Foundation for the Talents of the State Education Commission
文摘We prove the existence of global attractors in H0^1 （Ω） for a nonclassical diffusion equation. Two types of nonlinearity f are considered： one is the critical exponent, and the other is the polynomial growth of arbitrary order.
