共查询到20条相似文献,搜索用时 937 毫秒
1.
Wan-Fang Liu Heng-Na Xiong Jian Ma Xiaoguang Wang 《International Journal of Theoretical Physics》2010,49(5):1073-1081
We investigate the quantum Fisher information (QFI) of symmetric states for spin-s particles. We derive the maximal QFI, and find that quantum spin correlations are essential ingredients of the maximal QFI.
We make applications to the generalized one-axis twisting model. The results show that the redistributions of uncertainties
on the basis of the quantum correlations in the multiqubit system are useful for sub-shot-noise phase sensitivity. Furthermore,
for high-spin (s>1/2) composite systems, we find a sufficient criterion for entanglement. 相似文献
2.
The even and odd coherent states of a deformed harmonic oscillator in a finites-dimensional Hilbert space are studied. It is shown that both fors even ands odd, the even q-coherent states exhibit quadrature and amplitude-squared squeezing, while the odd q-coherent states show
an antibunching effect and amplitude-squared squeezing. 相似文献
3.
Ye-Jun Xu Hong-Chun Yuan Qiu-Yu Liu 《International Journal of Theoretical Physics》2010,49(5):1106-1117
A new class of excited two-mode generalized squeezed vacuum states denoted by |r,s,m,n〉 are presented, which are obtained by repeatedly applying creation operators a
†
and b
†
on the two-mode generalized squeezed vacuum state. We find that it is just regarded as a generalized squeezed two-variable
Hermite polynomial excitation on the vacuum state and its normalization constant is just a Jacobi polynomial. Their statistical
properties are investigated such as squeezing properties, photon number distribution and the violations of Cauchy-Schwartz
inequality. Especially, the Wigner function for |r,s,m,n〉 depending on the excitation photon numbers is discussed graphically. 相似文献
4.
《中国物理 B》2019,(6)
The celebrated Majorana representation is exploited to investigate spin squeezing in different classes of pure symmetric states of N qubits with two distinct spinors, namely the Dicke-class of states. On obtaining a general expression for spin squeezing parameter, the variation of squeezing for different configurations is studied in detail. It is shown that the states in the Dicke-class, characterized by two-distinct non-orthogonal spinors, exhibit squeezing. 相似文献
5.
Gamal M Abd Al-Kader 《Pramana》1999,53(5):877-890
The linear amplifier with the superposition of displaced Fock states (DFS’s) as an input field is discussed. The s-parameterized characteristic function (CF) of linear amplifier for the superposition of two DFS’s is considered. Several
quantum statistical expectation values for the output of linear amplifier are evaluated once the time dependent CF has been
computed. The Glauber secondorder coherence function is calculated. The squeezing properties of the output field are studied.
The s-ordered quasiprobability distribution function (QDF) for the output of linear amplifier driven by DFS’s superposition is
investigated. The phase properties of the superposition of DFS’s are studied. The s-parameterized phase distribution, obtained by integrating the s-parameterized QDF over radial variable is illustrated. 相似文献
6.
We point out a limiting procedure which enables one to construct in supergravity theories non-gauge, linearized spin- fields with the aid of the supercovariantly constant spinors. We give an explicit application of the procedure for N = 2 supergravity. 相似文献
7.
Run-Sheng Wu 《International Journal of Theoretical Physics》2012,51(11):3387-3392
We investigate the spin squeezing of a 4-qubit state, which is superposed by a 4-qubit GHZ state and two W states with a relative phase. Numerically solution for spin squeezing parameter is given. It is shown that the parameter depends on the superposition coefficients and the relative phase. It is shown that spin squeezing exists over a relatively long time with increasing superposition coefficient γ and the smaller the value of relative phase is, the longer the time of existing spin squeezing. 相似文献
8.
Dong Yan Xiaoguang Wang Lijun Song Zhanguo Zong 《Central European Journal of Physics》2007,5(3):367-376
We consider the mean spin direction (MSD) of superpositions of two spin coherent states (SCS) | ± μ〉, and superpositions of | μ〉 and | μ*〉 with a relative phase. We find that the azimuthal angle exhibits a π transition for both states when we vary the relative phase. The spin squeezing of the states, and the bosonic counterpart
of the mean spin direction are also discussed.
相似文献
9.
Monir Hadiah Bint Amir Naila Iqbal Shahid 《International Journal of Theoretical Physics》2019,58(6):1776-1790
The photon-added coherent states of Barut-Girardello and Perelomov types are constructed using Holstein-Primakoff realization of the su(1, 1) Lie algebra. Basic properties of the constructed states have been discussed. In addition, their non-classical features have been analyzed by computing photon detection probability distribution, Mandel Q-parameter and quadrature squeezing. It is shown that SU(1, 1) photon-added coherent states may exhibit sub-Poissonian statistics and quadrature squeezing for a chosen set of parameters. Moreover, it has been observed that their non-classical behavior increases as the number of added-photons increases.
相似文献10.
G.M. Abd Al-Kader 《The European Physical Journal B - Condensed Matter and Complex Systems》1999,8(3):429-438
The s-parameterized characteristic function for the output field with the superposition of squeezed displaced Fock states (SDFS's)
as input field is given. The s-ordered distribution functions for the output field with superposition of SDFS's as input state are investigated. Various
moments are calculated by using the s-ordered characteristic function for that field. The Glauber second-order coherence function is calculated. The quadrature
squeezing for the output field are discussed. Some Quasiprobability distribution functions of the output fields are plotted
as functions of the interaction time. The quadrature squeezing for the output field are discussed.
Received 30 September 1998 相似文献
11.
We express the density matrix for the N-qubit symmetric state or spin-j state (j = N/2) in terms of the well-known Fano statistical tensor parameters. Employing the multi-axial representation, where the spin-j density matrix is shown to be characterized by j(2j + 1) axes and 2j real scalars, we enumerate the number of invariants constructed out of these axes and scalars. We calculate these invariants
explicitly in the particular case of the pure and mixed spin-1 state. 相似文献
12.
Wan-Fang Liu Li-Hua Zhang Chun-Jie Li 《International Journal of Theoretical Physics》2010,49(10):2463-2475
In terms of quantum Fisher information (QFI), a quantity χ
2 was introduced by Pezzé and Smerzi (Phys. Rev. Lett. 102 100401, 2009). They pointed out that the inequality χ
2<1 was a sufficient condition for multiparticle entanglement. For the two-qubit symmetric states, we found that the inequality
χ
2<1 is a necessary and sufficient condition for entanglement and spin squeezing, and that χ
2 is equal to the second kind of spin squeezing parameter x22\xi _{2}^{2}. For the two-qubit asymmetric states, it is only a sufficient condition. In order to make it a necessary and sufficient condition,
we extend the concept of the QFI and χ
2, and generalize the relations among the entanglement measurement, the spin squeezing parameters and χ
2 in symmetric pure states to arbitrary pure states. 相似文献
13.
Hong-Chun Yuan Heng-Mei Li Ye-Jun Xu Hong-Yi Fan 《International Journal of Theoretical Physics》2009,48(12):3319-3330
A class of generalized two-mode squeezed states |φ〉 is presented, which are generated from the generalized two-mode squeezing operator U(γ,λ) acting on the two-mode coherent state |α
1,α
2〉. We first investigate some mathematical properties of U(γ,λ) including the squeezing transformation under U(γ,λ), ket-bra integral form in the coordinate representation, normally ordered form. Then we evaluate some nonclassical characteristics
of the state |φ〉 such as higher-order squeezing behavior, entanglement analysis and analytical expression of the Wigner function. 相似文献
14.
Lars Andersson Thomas Bäckdahl Jérémie Joudioux 《Communications in Mathematical Physics》2014,331(2):755-803
In this paper we analyze Hertz potentials for free massless spin-s fields on the Minkowski spacetime, with data in weighted Sobolev spaces. We prove existence and pointwise estimates for the Hertz potentials using a weighted estimate for the wave equation. This is then applied to give weighted estimates for the solutions of the spin-s field equations, for arbitrary half-integer s. In particular, the peeling properties of the free massless spin-s fields are analyzed for initial data in weighted Sobolev spaces with arbitrary, non-integer weights. 相似文献
15.
V. Chithiika Ruby M. Senthilvelan 《International Journal of Theoretical Physics》2014,53(12):4338-4350
We construct photon modulated coherent states of a generalized isotonic oscillator by expanding the newly introduced superposed operator through Weyl ordering method. We evaluate the parameter A 3 and the s-parameterized quasi probability distribution function to confirm the non - classical nature of the states. We also calculate the identities related with the quadrature squeezing to explore the squeezing property of the states. Finally, we investigate the fidelity between the photon modulated coherent states and coherent states to quantify the non-Gaussianity of the states. The constructed states and their associated non - classical properties will add further knowledge on the potential. 相似文献
16.
《Nuclear Physics B》1995,446(3):461-484
We study integrable vertex models and quantum spin chains with toroidal boundary conditions. An interesting class of such boundaries is associated with non-diagonal twist matrices. For such models there are no trivial reference states upon which a Bethe ansatz calculation can be constructed, in contrast to the well-known case of periodic boundary conditions. In this paper we show how the transfer matrix eigenvalue expression for the spin-s XXZ chain twisted by the charge-conjugation matrix can in fact be obtained. The technique used is the generalization to spin-s of the functional relation method based on “pair propagation through a vertex”. The Bethe ansatz-type equations obtained reduce, in the case of lattice size N = 1, to those recently found for the Hofstadter problem of Bloch electrons on a square lattice in a magnetic field. 相似文献
17.
M. Darwish 《International Journal of Theoretical Physics》2008,47(11):3035-3056
In this paper the even and odd nonlinear negative binomial states of the radiation field are introduced. These states interpolates
between even (odd) number states and the even (odd) nonlinear coherent states. The Glauber second-order correlation function
is calculated for these states. The squeezing phenomenon (normal and amplitude-squared squeezing), the quasi-probability distribution
function Q-function, Wigner-function and the phase properties, are also discussed. Examination of the resonance fluorescence against
the present state is given. It has been shown that the atomic inversion is sensitive to any variation in the even and odd
nonlinear negative binomial number M and the nonlinearity parameter η. 相似文献
18.
Yu-Xiao Liu Shao-Wen Wei Li-Jie Zhang Ji-Rong Ren 《The European Physical Journal C - Particles and Fields》2009,60(4):675-684
In this paper, we mainly investigate the W
2,s
M
⊗
W
2,s
L system, in which the matter and the Liouville subsystems generate the W
2,s
M and W
2,s
L algebras, respectively. We first give a brief discussion of the physical states for the corresponding W strings. The lower states are given by freezing the spin-2 and spin-s currents. Then, introducing two pairs of ghost-like fields, we give the realizations of the W
1,2,s
algebras. Based on these linear realizations, the BRST operators for the W
2,s
algebras are obtained. Finally, we construct new BRST charges of the Liouville system for the W
2,s
L strings at the specific values of the central charges c:
for the W
2,3L algebra, c=−24 for the W
2,4L algebra and
for the W
2,6L algebra, at which the corresponding W
2,s
L algebras are singular. 相似文献
19.
Xiao-Jie Yi Guo-Qiang Huang Jian-Min Wang 《International Journal of Theoretical Physics》2012,51(9):2960-2965
We investigate the spin squeezing in superpositions of a N-qubit GHZ state and two W states. The spin squeezing parameter is determined by the superposition coefficients and the relative phase. It is shown that there is squeezing in the n 2 direction and there is no squeezing in the n 1 direction. It is also shown that the state with more number of qubits has smaller spin squeezing parameter. 相似文献
20.
David A. Owen 《Foundations of Physics》1997,27(1):57-66
We develop here the general treatment of the Bethe—Salpeter equation for the bound state of two spin-l particles interacting through an electromagnetic interaction. The treatment here, which can be generalized to strong interactions,
combines the two-component approach utilized previously by the author in conjunction with spontaneous symmetry breaking. This
is done by using a Lagrangian having SU(2)×U(1) symmetry (without fermions) and then choosing the ′t Hooft gauge. In this way, a renormalizable theory for the interaction
of two spin-l particles via an electromagnetic interaction is ensured. 相似文献