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Quantum dense coding has been demonstrated experimentally in terms of quantum logic gates and circuits in quantum computation and NMR technique. Two bits of information have been transmitted through manipulating one of the maximally…

Quantum Physics · Physics 2009-10-31 Ximing Fang , Xiwen Zhu , Mang Feng , Xi'an Mao , Fei Du

Analytical expressions for the entanglement measures concurrence, i-concurrence and 3-tangle in terms of spin correlation functions are derived using general symmetries of the quantum spin system. These relations are exploited for the…

Quantum Physics · Physics 2009-11-10 Ulrich Glaser , Helmut Büttner , Holger Fehske

We introduce a new measure called reduced entropy of sublattice to quantify entanglement in spin, electron and boson systems. By analyzing this quantity, we reveal an intriguing connection between quantum entanglement and quantum phase…

Quantum Physics · Physics 2009-11-11 Y. Chen , Z. D. Wang , F. C. Zhang

The interaction between two quantum bits enables entanglement, the two-particle correlations that are at the heart of quantum information science. In semiconductor quantum dots much work has focused on demonstrating single spin qubit…

Mesoscale and Nanoscale Physics · Physics 2011-03-14 Danny Kim , Samuel G. Carter , Alex Greilich , Allan Bracker , Daniel Gammon

Quantum networks are an integral component in performing efficient computation and communication tasks that are not accessible using classical systems. A key aspect in designing an effective and scalable quantum network is generating…

Quantum Physics · Physics 2018-07-10 Sudipto Singha Roy , Himadri Shekhar Dhar , Debraj Rakshit , Aditi Sen De , Ujjwal Sen

In this article, we present a novel approach to investigating entanglement in the context of quantum computing. Our methodology involves analyzing reduced density matrices at different stages of a quantum algorithm's execution and…

Quantum Physics · Physics 2024-03-14 Ruge Lin

Bipartite entanglement in the ground state of a chain of $N$ quantum spins can be quantified either by computing pairwise concurrence or by dividing the chain into two complementary subsystems. In the latter case the smaller subsystem is…

Quantum Physics · Physics 2007-12-04 J. P. Keating , F. Mezzadri , M. Novaes

We describe an efficient theoretical criterion, suitable for indistinguishable particles to quantify the quantum correlations of any pure two-fermion state, based on the Slater rank concept. It represents the natural generalization of the…

Quantum Physics · Physics 2007-05-23 Fabrizio Buscemi , Paolo Bordone , Andrea Bertoni

Two-electron charged self-assembled quantum dot molecules exhibit a decoherence-avoiding singlet-triplet qubit subspace and an efficient spin-photon interface. We demonstrate quantum entanglement between emitted photons and the spin-qubit…

Mesoscale and Nanoscale Physics · Physics 2017-12-27 Yves L. Delley , Martin Kroner , Stefan Fält , Werner Wegscheider , Ataç İmamoğlu

We present a theoretical study of the relationship between entanglement and entropy in multi-qubit quantum optical systems. Specifically we investigate quantitative relations between the concurrence and linear entropy for a two-qubit mixed…

Quantum Physics · Physics 2009-11-10 Alexandra Olaya-Castro , Neil F. Johnson , Luis Quiroga

We address the effects of natural three-qubit interactions on the computational power of one-way quantum computation (\QC). A benefit of using more sophisticated entanglement structures is the ability to construct compact and economic…

Quantum Physics · Physics 2013-05-29 M. S. Tame , M. Paternostro , M. S. Kim , V. Vedral

Entanglement is at the core of quantum information processing and may prove essential for quantum speed-up. Inspired by both theoretical and experimental studies of spin-momentum coupling in systems of ultra-cold atoms, we investigate the…

Quantum Physics · Physics 2020-10-29 Sumit Suresh Kale , Yijue Ding , Yong P. Chen , Bretislav Friedrich , Sabre Kais

Gate-based universal quantum computation is formulated in terms of two types of operations: local single-qubit gates, which are typically easily implementable, and two-qubit entangling gates, whose faithful implementation remains one of the…

Quantum Physics · Physics 2023-10-18 Xiaoqin Gao , Paul Appel , Nicolai Friis , Martin Ringbauer , Marcus Huber

Inspired by the close relationship between Kolmogorov complexity and unsupervised machine learning, we explore quantum circuit complexity, an important concept in quantum computation and quantum information science, as a pivot to understand…

Quantum Physics · Physics 2026-04-29 Yanming Che , Clemens Gneiting , Xiaoguang Wang , Franco Nori

Recently developed quantum algorithms suggest that quantum computers can solve certain problems and perform certain tasks more efficiently than conventional computers. Among other reasons, this is due to the possibility of creating…

Quantum Physics · Physics 2007-05-23 Rolando D. Somma

Optically connecting quantum bits can effectively reduce decoherence and facilitate long-distance communication. Optically addressable spin-bearing molecules have been demonstrated to have a good potential for quantum computing. In this…

Quantum Physics · Physics 2023-03-28 Jiawei Chang , Tianhong Huang , Lin Ma , Taoyu Zou , Hai Wang , Wei Wu

We consider two interacting electrons in a semiconductor quantum dot structure which consists of a small dot within a larger dot, and demonstrate a singlet-triplet filtering mechanism which involves spin-dependent resonances and can…

Mesoscale and Nanoscale Physics · Physics 2009-11-11 G. Giavaras , J. H. Jefferson , M. Fearn , C. J. Lambert

The electron spin state of a singly charged semiconductor quantum dot has been shown to form a suitable single qubit for quantum computing architectures with fast gate times. A key challenge in realizing a useful quantum dot quantum…

Optimal control techniques are applied for the decomposition of unitary quantum operations into a sequence of single-qubit gates and entangling operations. To this end, we modify a gradient-ascent algorithm developed for systems of coupled…

Quantum Physics · Physics 2009-01-15 V. Nebendahl , H. Haffner , C. F. Roos

Modern quantum optical systems such as photonic quantum computers and quantum imaging devices require great precision in their designs and implementations in the hope to realistically exploit entanglement and reach a real quantum advantage.…

Quantum Physics · Physics 2024-06-05 Nicolas Allegra