Nonstandard Unitary Transformations of Quantum States

In quantum optics, unitary transformations of arbitrary states are evaluated by using the Taylor series expansion. However, this traditional approach can become cumbersome for the transformations involving non-commuting operators. Addressing this issue, a nonstandard unitary transformation technique is highlighted here with new perspective. In a spirit of “quantum” series expansions, the transition probabilities between initial and final states, such as displaced, squeezed and other nonlinearly transformed coherent states are obtained both numerically and analytically. This paper concludes that, although this technique is novel, its implementations for more extended systems are needed.

Verifiable quantum secret sharing scheme based on orthogonal product states

In the domain of quantum cryptography,the implementation of quantum secret sharing stands as a pivotal element.In this paper,we propose a novel verifiable quantum secret sharing protocol using the d-dimensional product state and Lagrange interpolation techniques.This protocol is initiated by the dealer Alice,who initially prepares a quantum product state,selected from a predefined set of orthogonal product states within the C~d■C~d framework.Subsequently,the participants execute unitary operations on this product state to recover the underlying secret.Furthermore,we subject the protocol to a rigorous security analysis,considering both eavesdropping attacks and potential dishonesty from the participants.Finally,we conduct a comparative analysis of our protocol against existing schemes.Our scheme exhibits economies of scale by exclusively employing quantum product states,thereby realizing significant cost-efficiency advantages.In terms of access structure,we adopt a(t, n)-threshold architecture,a strategic choice that augments the protocol's practicality and suitability for diverse applications.Furthermore,our protocol includes a rigorous integrity verification mechanism to ensure the honesty and reliability of the participants throughout the execution of the protocol.

A note on local unitary equivalence of isotropic-like states

We consider the local unitary equivalence of a class of quantum states in a bipartite case and a multipartite case. The necessary and sufficient condition is presented. As special cases, the local unitary equivalent classes of isotropic state and Werner state are provided. Then we study the local unitary similar equivalence of this class of quantum states and analyze the necessary and sufficient condition.

Squeezed Coherent States in Non-Unitary Approach and Relation to Sub- and Super-Poissonian Statistics

After developing the concept of displaced squeezed vacuum states in the non-unitary approach and establishing the connection to the unitary approach we calculate their quasiprobabilities and expectation values in general form. Then we consider the displacement of the squeezed vacuum states and calculate their photon statistics and their quasiprobabilities. The expectation values of the displaced states are related to the expectation values of the undisplaced states and are calculated for some simplest cases which are sufficient to discuss their categorization as sub-Poissonian and super-Poissonian statistics. A large set of these states do not belong to sub- or to super-Poissonian states but are also not Poissonian states. We illustrate in examples their photon distributions. This shows that the notions of sub- and of super-Poissonian statistics and their use for the definition of nonclassicality of states are problematic. In Appendix A we present the most important relations for SU (1,1) treatment of squeezing and the disentanglement of their operators. Some initial members of sequences of expectation values for squeezed vacuum states are collected in Appendix E.

Matrix Tensor Product Approach to the Equivalence of Multipartite States under Local Unitary Transformations

混合的多国参加的量的等价在本地人下面声明单一的转变被学习。为在本地单一的转变下面的非退化的混合的多国参加的量状态的等价的一个标准被介绍。

Degenerate States in Nonlinear Sigma Model with SU(2) Symmetry

Entanglement in quantum theory is a peculiar concept to scientists. With this concept we are forced to re-consider the cluster property which means that one event is irrelevant to another event when they are fully far away. In the recent works we showed that the quasi-degenerate states induce the violation of cluster property in antiferromagnets when the continuous symmetry breaks spontaneously. We expect that the violation of cluster property will be observed in other materials too, because the spontaneous symmetry breaking is found in many systems such as the high temperature superconductors and the superfluidity. In order to examine the cluster property for these materials, we studied a quantum nonlinear sigma model with U(1) symmetry in the previous work. There we showed that the model does have quasi-degenerate states. In this paper we study the quantum nonlinear sigma model with SU(2) symmetry. In our approach we first define the quantum system on the lattice and then adopt the representation where the kinetic term is diagonalized. Since we have no definition on the conjugate variable to the angle variable, we use the angular momentum operators instead for the kinetic term. In this representation we introduce the states with the fixed quantum numbers and carry out numerical calculations using quantum Monte Carlo methods and other methods. Through analytical and numerical studies, we conclude that the energy of the quasi-degenerate state is proportional to the squared total angular momentum as well as to the inverse of the lattice size.

秦汉时期统一多民族国家语境下的“中国”认同

在统一多民族国家的政治环境和“天下一家”语境下,四裔归属意识的不断增强,是秦汉时期的“中国”认同获得空前发展的根本机制。郡县制管理体制机制下东西南北各地、各族居民先后被“编户化”而统称为“秦人”和“汉人”,意味着在秦汉王朝疆域版图之内各族居民在共同的政治、经济、文化政策下,相互认同而实现的空前民族统一,体现出当时东西南北各族对以秦汉王朝为代表的“中国”,在政治、经济、文化等维度下的全方位认同。这是中国古代国家形态、民族内涵及其关系格局发展过程中出现的一次具有里程碑意义的重大转机,这种直接以统一帝国疆域划定的规模空前的统一民族共同体的出现,对于后世中华民族共同体意识的凝聚,具有重要的奠基意义。

从光的生-灭机制阐述量子力学

通过引入有序算符内的积分理论,从光子产生–湮灭的观点出发来阐述量子力学理论,显示表象的正态分布,在数学上支持量子力学的几率假设;指出如何从经典变换直接过渡到量子幺正算符,自然地引入纠缠态表象,并指出数学物理研究的新方向.

任意三粒子GHZ态和W态的概率隐形传态

构造了一个全新的由两个多粒子部分纠缠态组成的用于量子隐形传态(QT)的量子信道。利用构造的量子信道,提出了两个任意三粒子GHZ态和W态的受控概率隐形传态的三方方案。发送者执行贝尔态测量和单粒子测量,控制者执行贝尔态测量,接收者引入一个辅助粒子并执行相应酉操作,可实现任意三粒子GHZ态和W态的概率隐形传送。两个QT方案的总成功概率都是8d^(2)n^(2)(其中d和n是量子信道的系数)。

“统一的多民族国家”:概念溯源与话语演变

“统一的多民族国家”是具有中国特色的政治概念和话语表达。既有研究侧重于对其进行历史证成和理论阐释,少有从概念史的层面对其进行概念溯源和话语演变的梳理。“统一的多民族国家”概念孕育于中国自古以来的“国家统一”话语,生成于中国共产党革命、建设和改革时期的社会实践,经新时代以来的理论创新,其概念内涵日益丰富,话语价值充分彰显,建构方式也逐渐明确。对其进行概念史的梳理,可以厘清这一概念和话语背后的政治意涵,深刻理解我国是“统一的多民族国家”的历史和国情,为推进中华民族共同体建设和实现中华民族的伟大复兴提供理论指引。

Probabilistic teleportation of an arbitrary three-particle state

A scheme for teleporting an arbitrary and unknown three-particle state from a sender to either one of two receivers is proposed. The quantum channel is composed of a two-particle non-maximally entangled state and two three-particle non-maximally entangled W states. An arbitrary three-particle state can be perfectly teleported probabilistically if the sender performs three generalized Bell-state measurements and sends to the two receivers the classical result of these measurements, and either one of the two receivers adopts an appropriate unitary transformation conditioned on the suitable measurement outcomes of the other receiver. All kinds of unitary transformations are given in detail.

How tightly is the nuclear symmetry energy constrained by a unitary Fermi gas?

We examine critically how tightly the density dependence of nuclear symmetry energy E_(sym)(q) is constrained by the universal equation of state of the unitary Fermi gas EUG(q) considering currently known uncertainties of higher order parameters describing the density dependence of the equation of state of isospin asymmetric nuclear matter. We found that E_(UG)(q) does provide a useful lower boundary for the E_(sym)(q). However, it doesnot tightly constrain the correlation between the magnitude E_(sym)(q_0) and slope L unless the curvature K_(sym)of the symmetry energy at saturation density q_0 is more precisely known. The large uncertainty in the skewness parameters affects the E_(sym)(q_0) versus L correlation by the same almost as significantly as the uncertainty in K_(sym).

Probabilistic teleportation of a non-symmetric three-particle state

This paper proposes a scheme for teleporting a kind of essential three-particle non-symmetric entangled state, which is much more valuable than a GHZ and W state for some applications in quantum information processing. In comparison with previous proposal of teleportation, the resources of entangled states as quantum channel and the number of classical messages required by our scheme can be cut down. Moreover, it is shown that there exists a class of transformations which ensure the success of this scheme, because the two-particle transformation performed by the receiver in the course of teleportation may be a generic two-particle operation instead of a control-NOT （CNOT） operation. In addition, all kinds of transformations performed by sender and receiver are given in detail.

Deterministic and exact entanglement teleportation via the W state

Utilizing a three-particle W state, we come up with a protocol for the teleportation of an unknown two-particle entangled state. It is shown that the teleportation can be deterministically and exactly realized. Moreover, two-particle entanglement teleportation is generalized to a system consisting of many particles via a three-particle W state and a multi-particle W state, respectively. All unitary transformations performed by the receiver are given in a concise formula.

Remote Preparation of a Two-Particle Entangled State by a Bipartite Entangled State and a Tripartite Entangled W State

我们建议一个计划遥远地由把一个由两部组成的纠缠的状态和一个分成三部分的纠缠的 W 状态用作量隧道准备一个一般二粒子的纠缠的状态。我们的计划由一个发送者和二遥远的接收装置组成。发送者能帮助任何一个一接收装置遥远地重建有另外的接收装置的帮助的原来的状态“ s 单个粒子的直角的测量。我们获得全部的成功概率并且在我们的遥远的州的准备计划讨论古典通讯费用。

Teleportation of a Three—Particle state via Entanglement Swapping

A scheme for teleporting a three-particle state is proposed when three pairs of entang]ed particles are used as quantum channel. After a sender operates the Bell-state measurement, the original state with deterministic probability can be reconstructed when the receiver performs a corresponding measurement with unitary transformation.

Teleportation of an Arbitrary Three-Particle State via Three EPR Pairs

A scheme of teleportation of an arbitrary three-particle state is presented when three pairs of entangled particles are used as quantum channels. After the Bell state measurements are operated by the sender, the original state with deterministic probability can be reconstructed by the receiver when a corresponding unitary transformation is followed.

Controlled Teleportation of an Arbitrary Two-Particle State by One EPR Pair and Cluster State

A scheme for controlled teleportation of an arbitrary two-particle state using a maximally entangled EPRpair and a cluster state as the quantum channel is proposed.After receiving Alice’s Bell state measurement results,the controller performs a joint measurement on his particles under a non-maximally entangled Bell-basis.The receiverneeds to introduce an auxiliary qubit,and performs a series of appropriate unitary transformations on his particles.Theoriginal state can be teleported successfully with the probability 2 cos2 9.

Teleportation of an Arbitrary Two-Particle State by Two Partial Entangled Three-Particle GHZ States

We present a scheme for teleporting an unknown arbitrary two-particle state from a sender to either one of two receivers. The quantum channel is composed of two partial entangled three-particle GHZ states. An unknown arbitrary two-particle state can be perfectly teleported probabilistically if the sender performs two generalized Bell-state measurements and each receiver introduces an appropriate unitary transformation with the help of the other receiver's Hadamard operations and simple measurements.

Probabilistic Teleportation of an Arbitrary Two-Particle State and Its Quantum Circuits

为用 non-maximally 纠缠的 EPR 对和 non-maximally 纠缠的 GHZ 的一个任意的 unknowntwo 粒子状态的概率的远距传物的二个简单计划作为量声明隧道被建议。在收到艾莉斯的贝尔状态测量结果以后， Bobperforms 他没有介绍辅助 qubit 的固有的粒子上的集体单一的转变。原来的状态能是移植的概率的联盟者电视。同时，为成功的远距传物的实现的量电路也被介绍。