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It is well known that qubits immersed in a squeezed vacuum environment exhibit many exotic phenomena, including dissipative entanglement stabilization. Here, we show that these effects only require interference between excitation and decay…

Quantum Physics · Physics 2023-07-25 L. C. G. Govia , A. Lingenfelter , A. A. Clerk

We study the use of squeezed light for qubit coherent control and compare it with the coherent state control field case. We calculate the entanglement between a short pulse of resonant squeezed light and a two-level atom in free space and…

Quantum Physics · Physics 2013-05-29 Ephraim Shahmoon , Shimon Levit , Roee Ozeri

In this work, we study a bipartite system composed by a pair of entangled qudits coupled to an environment. Initially, we derive a master equation and show how the dynamics can be restricted to a "diagonal" sector that includes a maximally…

Quantum Physics · Physics 2018-04-04 L. E. Oxman , A. Z. Khoury , F. C. Lombardo , P. I. Villar

Quantum hardware is advancing rapidly across various platforms, yet implementing large-scale quantum error correction (QEC) remains challenging. As hardware continues to improve, there is a growing need to identify potential applications on…

Quantum Physics · Physics 2025-08-04 Gyungmin Cho , Dohun Kim

This paper is a continuation of our previous paper [8], in which we have studied the dynamics of quantum correlations of two qubits embedded each into its own disordered multiconnected environment. We modeled the environment by random…

Quantum Physics · Physics 2020-05-12 Ekaterina Bratus , Leonid Pastur

We study the dynamics of a two-level quantum system interacting with an external electromagnetic field periodic and quasiperiodic in time. The quantum evolution is described exactly by the classical equations of motion of a gyromagnet in a…

Quantum Physics · Physics 2009-11-11 Renato M. Angelo , Walter F. Wreszinski

We investigate the time evolution of entanglement for bipartite systems of arbitrary dimensions under the influence of decoherence. For qubits, we determine the precise entanglement decay rates under different system-environment couplings,…

Quantum Physics · Physics 2007-05-23 André R. R. Carvalho , Florian Mintert , Stefan Palzer , Andreas Buchleitner

Entanglement is one of the key resources required for quantum computation, so experimentally creating and measuring entangled states is of crucial importance in the various physical implementations of a quantum computer. In superconducting…

In this paper we utilize superoperator formalism to explore the entanglement evolution of four-qubit cluster states in a number of decohering environments. A four-qubit cluster state is a resource for the performance of an arbitrary single…

Quantum Physics · Physics 2015-05-20 Yaakov S. Weinstein , Jay Feldman , Jacob Robins , Jason Zukus , Gerald Gilbert

Qubits encoded in a decoherence-free subsystem and realized in exchange-coupled silicon quantum dots are promising candidates for fault-tolerant quantum computing. Benefits of this approach include excellent coherence, low control…

We consider continuous quantum measurement of a superconducting qubit in the circuit QED setup with a moderate bandwidth of the measurement resonator, i.e., when the "bad cavity" limit is not applicable. The goal is a simple description of…

Quantum Physics · Physics 2016-10-26 Alexander N. Korotkov

Two-qubit gates in trapped-ion quantum computers are generated by applying spin-dependent forces that temporarily entangle the internal state of the ion with its motion. Laser pulses are carefully designed to generate a maximally entangling…

Quantum Physics · Physics 2021-12-21 Mingyu Kang , Qiyao Liang , Bichen Zhang , Shilin Huang , Ye Wang , Chao Fang , Jungsang Kim , Kenneth R. Brown

Predictions for systems in entangled states cannot be described in local realistic terms. However, after admixing some noise such a description is possible. We show that for two quNits (quantum systems described by N dimensional Hilbert…

Quantum Physics · Physics 2013-05-29 Thomas Durt , Dagomir Kaszlikowski , Marek Zukowski

We explore the quantum-classical crossover of two coupled, identical, superconducting quantum interference device (SQUID) rings. The motivation for this work is based on a series of recent papers. In ~[1] we showed that the entanglement…

Quantum Physics · Physics 2010-01-13 M. J. Everitt

The ability to reach a maximally entangled state from a separable one through the use of a two-qubit unitary operator is analyzed for mixed states. This extension from the known case of pure states shows that there are at least two families…

Quantum Physics · Physics 2018-04-06 Zhe Guan , Huan He , Yong-Jian Han , Chuan-Feng Li , Fernando Galve , Guang-Can Guo

Quantum algorithms on near-term quantum processors are typically executed using shallow quantum circuits composed of one- and two-qubit gates. However, as circuit depth and gate number increase, gate imperfections and qubit decoherence…

In circuit-based quantum computing, the available gate set typically consists of single-qubit gates acting on each individual qubit and at least one entangling gate between pairs of qubits. In certain physical architectures, however, some…

Quantum Physics · Physics 2022-09-23 M. Pechal , G. Salis , M. Ganzhorn , D. J. Egger , M. Werninghaus , S. Filipp

We demonstrate an all-microwave two-qubit gate on superconducting qubits which are fixed in frequency at optimal bias points. The gate requires no additional subcircuitry and is tunable via the amplitude of microwave irradiation on one…

The speed of quantum evolution is limited under finite energy resources. While most quantum speed limits (QSLs) are formulated in terms of quantum states, they can be extended to the evolution operator itself, and thus impose fundamental…

Quantum Physics · Physics 2026-04-28 Hunter Nelson , Edwin Barnes

Entanglement and steering are used to describe quantum inseparabilities. Steerable states form a strict subset of entangled states. A natural question arises concerning how much territory steerability occupies entanglement for a general…

Quantum Physics · Physics 2021-09-01 Xiao-Gang Fan , Huan Yang , Fei Ming , Zhi-Yong Ding , Dong Wang , Liu Ye