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Distributed quantum information processing is a promising platform for scaling up quantum information processing, where small- and intermediate-scale quantum devices are connected by a network of quantum channels for communicating quantum…

Quantum Physics · Physics 2019-03-26 Hayata Yamasaki

High-dimensional entangled states are promising candidates for increasing the security and encoding capacity of quantum systems. While it is possible to witness and set bounds for the entanglement, precisely quantifying the dimensionality…

We consider quantum systems in entangled states post-selected in non-entangled states. Such systems exhibit unusual behavior, in particular when weak measurements are performed at intermediate times.

Quantum Physics · Physics 2015-06-12 Yakir Aharonov , Shmuel Nussinov , Sandu Popescu , Lev Vaidman

A recent experiment [Lanting et al., PRX, (2014)] claimed to provide evidence of up to $8$-qubit entanglement in a D-Wave quantum annealing device. However, entanglement was measured using qubit tunneling spectroscopy, a technique that…

Quantum Physics · Physics 2015-12-17 Tameem Albash , Itay Hen , Federico M. Spedalieri , Daniel A. Lidar

We propose a linear-optical implementation of a hyperentanglement-assisted quantum error-correcting code. The code is hyperentanglement-assisted because the shared entanglement resource is a photonic state hyperentangled in polarization and…

Quantum Physics · Physics 2009-10-23 Mark M. Wilde , Dmitry B. Uskov

We investigate several aspects of realizing quantum computation using entangled polar molecules in pendular states. Quantum algorithms typically start from a product state |00...0> and we show that up to a negligible error, the ground…

Quantum Physics · Physics 2016-07-19 Qi Wei , Yudong Cao , Sabre Kais , Bretislav Friedrich , Dudley Herschbach

This Letter verifies the potential of several classes of entangled coherent state in well known quantum metrology which includes detection of classical external force, and shows that there is a class of entangled coherent state for the…

Quantum Physics · Physics 2012-01-10 Osamu Hirota , Kentaro Kato , Dan Murakami

Based on the realignment moments of density matrix, we study parameterized entanglement criteria for bipartite and multipartite states. By adjusting the different parameter values, our criterion can detect not only bound entangled states,…

Quantum Physics · Physics 2025-10-13 Hui Zhao , Shu-Ying Zhuang , Naihuan Jing , Mei-Ming Zhang

Entanglement is a crucial quantum resource with broad applications in quantum information science. For harnessing entanglement in practice, it is a prerequisite to certify the entanglement of a given quantum state. However, the…

Quantum Physics · Physics 2023-10-11 Hyeon-Jin Kim , Ji-Hyeok Jung , Kyung-Jun Lee , Young-Sik Ra

It was shown in [T. Morimae, Phys. Rev. A {\bf81}, 060307(R) (2010)] that the gate fidelity of an inaccurate one-way quantum computation is upper bounded by a decreasing function of the amount of entanglement in the register. This means…

Quantum Physics · Physics 2015-05-20 Tomoyuki Morimae , Jonas Kahn

Entanglement-assisted discrimination of orthogonal quantum states exhibiting quantum nonlocality is a frontier topic in quantum information theory. In this paper, we investigate the role of multipartite entanglement and develop…

Quantum Physics · Physics 2026-03-18 Ziying Hou , Huaqi Zhou , Limin Gao

Distributed quantum computing offers a promising approach to scaling quantum devices by networking multiple quantum processors. We present a quantum state tomography protocol tailored for distributed quantum computers that avoids assuming…

Quantum Physics · Physics 2026-04-27 Hans Mättig-Vásquez , Aldo Delgado , Luciano Pereira

Adaptive quantum circuits, leveraging measurements and classical feedback, significantly expand the landscape of realizable quantum states compared to their non-adaptive counterparts, enabling the preparation of long-range entangled states…

Quantum Physics · Physics 2025-09-23 Guoding Liu , Junjie Chen , Xiongfeng Ma

Quantum state tomography is a technique in quantum information science used to reconstruct the density matrix of an unknown quantum state, providing complete information about the quantum state. It is of significant importance in fields…

Quantum Physics · Physics 2025-07-23 Wenlong Zhao , Da Zhang , Huili Zhang , Haifeng Yu , Zhang-qi Yin

The efficient and reliable certification of quantum states is essential for various quantum information processing tasks as well as for the general progress on the implementation of quantum technologies. In the last few years several…

Quantum Physics · Physics 2022-05-10 Xiao-Dong Yu , Jiangwei Shang , Otfried Gühne

We explore entanglement as a resource to distinguish locally indistinguishable orthogonal quantum states. Specifically, we consider sets which contain states from an unextendible product basis along with a pure entangled state. We establish…

Quantum Physics · Physics 2025-09-30 Abhay Srivastav , Saronath Halder

Detection of entangled states is essential in both fundamental and applied quantum physics. However, this task proves to be challenging especially for general quantum states. One can execute full state tomography but this method is time…

Quantum Physics · Physics 2021-05-12 Jan Roik , Karol Bartkiewicz , Antonín Černoch , Karel Lemr

We investigate quantum repeater protocols based upon atomic qubit-entanglement distribution through optical coherent-state communication. Various measurement schemes for an optical mode entangled with two spatially separated atomic qubits…

Quantum Physics · Physics 2010-12-14 Peter van Loock , Norbert Lütkenhaus , W. J. Munro , Kae Nemoto

We introduce measurement-based quantum repeaters, where small-scale measurement-based quantum processors are used to perform entanglement purification and entanglement swapping in a long-range quantum communication protocol. In the scheme,…

Quantum Physics · Physics 2013-06-03 M. Zwerger , W. Dür , H. J. Briegel

Armed with quantum correlations, quantum sensors in a network have shown the potential to outclass their classical counterparts in distributed sensing tasks such as clock synchronization and reference frame alignment. On the other hand,…

Quantum Physics · Physics 2024-05-24 Yuxiang Yang , Benjamin Yadin , Zhen-Peng Xu