English
Related papers

Related papers: Are all noisy quantum states obtained from pure on…

200 papers

Heterogeneous bipartite quantum pure states, composed of two subsystems with a different number of levels, cannot have both reductions maximally mixed. In this work, we demonstrate existence of a wide range of highly entangled states of…

Quantum Physics · Physics 2016-08-06 D. Goyeneche , J. Bielawski , K. Życzkowski

Quantum coherence, the physical property underlying fundamental phenomena such as multi-particle interference and entanglement, has emerged as a valuable resource upon which modern technologies are founded. In general, the most prominent…

The task of learning a quantum circuit to prepare a given mixed state is a fundamental quantum subroutine. We present a variational quantum algorithm (VQA) to learn mixed states which is suitable for near-term hardware. Our algorithm…

The monogamy relation for quantum correlations is not satisfied by all measures for all multiparty quantum states. We prove that an arbitrary quantum state which is nonmonogamous for negativity will become monogamous if a finite number of…

Quantum Physics · Physics 2018-07-13 Saptarshi Roy , Tamoghna Das , Asutosh Kumar , Aditi Sen De , Ujjwal Sen

We reduce the question whether a given quantum mixed state is separable or entangled to the problem of existence of a certain full family of commuting normal matrices whose matrix elements are partially determined by components of the pure…

Quantum Physics · Physics 2009-11-13 Jan Samsonowicz , Marek Kus , Maciej Lewenstein

We give necessary conditions for the mixing problem in bipartite case, which are independent of eigenvalues and based on algebraic-geometric invariants of the bipartite states. One implication of our results is that for some special…

Quantum Physics · Physics 2007-05-23 Hao Chen

It is shown that generic N-party pure quantum states (with equidimensional subsystems) are uniquely determined by their reduced states of just over half the parties; in other words, all the information in almost all N-party pure states is…

Quantum Physics · Physics 2009-11-10 Nick S. Jones , Noah Linden

We focus our attention on two-qubit mixed states as initial states, and apply the geometric measure of quantum discord to investigate quantum discord properties in the background of a Schwarzschild black hole under phase damping, phase flip…

Quantum Physics · Physics 2026-04-08 Yuxuan Xiong , Zhiling Pi , Tinggui Zhang , Xiaofen Huang

Uncertainties in the frequency parameters of a frequency comb laser, causes it to represent a mixed quantum state. The formulation of such a quantum state is compounded by the fact that it contains both particle-number degrees of freedom…

Quantum Physics · Physics 2017-06-05 Filippus S. Roux

Mixed states are introduced in physics in order to express our ignorance about the actual state of a physical system and are represented in standard quantum mechanics (QM) by density operators. Such operators also appear if one considers a…

Quantum Physics · Physics 2014-11-13 Claudio Garola , Sandro Sozzo

The completeness of quantum state space, is usually expressed as \sum_{m=0}^{\infty}|m><m|=1, where {|m>} is selected set of quantum states (basis). Density matrix |m><m| describes a pure quantum state. In this paper, by virtue of the…

Quantum Physics · Physics 2017-11-28 Hongyi Fan , Jun-hua Chen , Dehui Zhan , Liyun Hu

The N to M (M>N) universal quantum broadcasting of mixed states are proposed for qubits system. The broadcasting of mixed states is universal and optimal in the sense that the shrinking factor is independent of input state and achieves the…

Quantum Physics · Physics 2009-11-13 Gui-Fang Dang , Heng Fan

In this paper, we study the quantum states generated from two and three linearly interacting quantum harmonic oscillators. We consider the possibility that one of the oscillators be under the influence of a classical external source and…

Quantum Physics · Physics 2022-09-27 Haqi Ismael Shareef , Fardin Kheirandish

We investigate the correlation properties of separable two qubit states with maximally mixed marginals. These states are divided to two sets with the same geometric quantum correlation. However a closer scrutiny of these states reveals a…

Quantum Physics · Physics 2015-01-14 Azam Mani , Vahid Karimipour , Laleh Memarzadeh

We propose a scheme to evaluate the amount of quantum discord and entanglement of formation for mixed states, and reveal their ordering relation via an intrinsic relationship between the two quantities distributed in different partners of…

Quantum Physics · Physics 2015-05-19 Li-Xiang Cen , Xin-Qi Li , JiuShu Shao , YiJing Yan

We show that not all 4-party pure states are GHZ reducible (i.e., can be generated reversibly from a combination of 2-, 3- and 4-party maximally entangled states by local quantum operations and classical communication asymptotically)…

Quantum Physics · Physics 2009-11-06 Shengjun Wu , Yongde Zhang

We consider the separability of various joint states of D-dimensional quantum systems, which we call "qudits." We derive two main results: (i) the separability condition for a two-qudit state that is a mixture of the maximally mixed state…

Quantum Physics · Physics 2012-01-04 P. Rungta , W. J. Munro , K. Nemoto , P. Deuar , G. J. Milburn , C. M. Caves

The key observation about quantum reality is that it often appears as if, at some moment, the probability of a quantum event becomes a definite outcome for us. A careful analysis suggests, however, that what we perceive as a definite state…

General Physics · Physics 2025-10-22 Aleksandar Perisic

Absolutely maximally entangled states are quantum states that exhibit maximal entanglement across any bipartition, making them valuable for applications. This study investigates the behavior of qubit AME states under the influence of noisy…

Quantum Physics · Physics 2025-05-13 Maria Stawska , Jan Wójcik , Andrzej Grudka , Antoni Wójcik

It is argued that proper and improper quantum mixed states have no observable differences, and hence should not be distinguished. This has implications for subjective approaches to quantum mechanics, and invalidates one of the main…

Quantum Physics · Physics 2022-01-13 Leonardo Castellani