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Pointer states are long-lasting high-fidelity states in open quantum systems. We show how any pure state in a non-Markovian open quantum system can be made to behave as a pointer state by suitably engineering the coupling to the environment…

Quantum Physics · Physics 2015-05-28 Kaveh Khodjasteh , Viatcheslav V. Dobrovitski , Lorenza Viola

Switching controlled dynamics allows for fast, flexible control design methods for quantum stabilization of pure states and subspaces, which naturally include both Hamiltonian and dissipative control actions. A novel approach to…

Quantum Physics · Physics 2024-06-24 Weichao Liang , Tommaso Grigoletto , Francesco Ticozzi

Engineered dissipation can be employed to prepare interesting quantum many body states in a non-equilibrium fashion. The basic idea is to obtain the state of interest as the unique steady state of a quantum master equation, irrespective of…

Quantum Gases · Physics 2015-04-16 Jan Carl Budich , Peter Zoller , Sebastian Diehl

Starting from an initial pure quantum state, we present a strategy for reaching a target state corresponding to the extremum (maximum or minimum) of a given observable. We show that a sequence of pulses of moderate intensity, applied at…

Quantum Physics · Physics 2016-08-16 D. Sugny , A. Keller , O. Atabek , D. Daems , C. M. Dion , S. Guérin , H. R. Jauslin

Disentanglement of a laser source from its target qubit is proposed as a criterion establishing the laser quantum state as a coherent state. It is shown that the source-target density operator has a unique factorization in coherent states…

Quantum Physics · Physics 2008-09-24 Changsuk Noh , H. J. Carmichael

In bulk quantum computation one can manipulate a large number of indistinguishable quantum computers by parallel unitary operations and measure expectation values of certain observables with limited sensitivity. The initial state of each…

Quantum Physics · Physics 2009-10-30 Emanuel Knill , Isaac Chuang , Raymond Laflamme

We propose an all-electronic technique to manipulate and control interacting quantum systems by unitary single-jump feedback conditioned on the outcome of a capacitively coupled electrometer and in particular a single-electron transistor.…

Mesoscale and Nanoscale Physics · Physics 2013-01-07 Gerold Kiesslich , Clive Emary , Gernot Schaller , Tobias Brandes

Passive states are special configurations of a quantum system which exhibit no energy decrement at the end of an arbitrary cyclic driving of the model Hamiltonian. When applied to an increasing number of copies of the initial density…

Quantum Physics · Physics 2020-06-02 Raffaele Salvia , Vittorio Giovannetti

In the quantum Zeno effect, quantum measurements can block the coherent oscillation of a two level system by freezing its state to one of the measurement eigenstates. The effect is conventionally controlled by the measurement frequency.…

Quantum Physics · Physics 2020-10-06 Kyrylo Snizhko , Parveen Kumar , Alessandro Romito

Inspired by natural cooling processes, dissipation has become a promising approach for preparing low-energy states of quantum systems. However, the potential of dissipative protocols remains unclear beyond certain commuting Hamiltonians.…

Quantum Physics · Physics 2026-02-27 Yongtao Zhan , Zhiyan Ding , Jakob Huhn , Johnnie Gray , John Preskill , Garnet Kin-Lic Chan , Lin Lin

We study nonequilibrium steady states (NESSs) in the weakly-coupled XXZ model in contact with two heat baths at different temperatures. We show that the density matrix can be represented using only projection operators specified by the…

Statistical Mechanics · Physics 2024-09-24 Shimpei Senda , Tatsuro Sunami , Yuto Matsumoto , Ayumu Sugita

We consider an open quantum system with dissipation, described by a Lindblad Master equation (LME). For dissipation locally acting and sufficiently strong, a separation of the relaxation time scales occurs, which, in terms of the…

Quantum Physics · Physics 2021-05-13 Vladislav Popkov , Carlo Presilla

We study the properties of the random quantum states induced from the uniformly random pure states on a bipartite quantum system by taking the partial trace over the larger subsystem. Most of the previous studies have adopted a viewpoint of…

Quantum Physics · Physics 2023-11-29 Eyuri Wakakuwa

In multistate non-Hermitian systems, higher-order exceptional points and exotic phenomena with no analogues in two-level systems arise. A paradigm is the exceptional nexus (EX), a third-order EP as the cusp singularity of exceptional arcs…

Quantum Physics · Physics 2024-06-21 Chenhao Wang , Nan Li , Jin Xie , Cong Ding , Zhonghua Ji , Liantuan Xiao , Suotang Jia , Ying Hu , Yanting Zhao

We propose a method to generate large cluster states without using conditional (e.g., CNOT, C-phase) gates. Indeed, an arbitrarily large cluster state can be generated and expanded almost deterministically by single-qubit rotations and a…

Quantum Physics · Physics 2009-11-13 Xiang-bin Wang , J. Q. You , Franco Nori

We investigate the quantum state discrimination task for sets of linear independent pure states with an intrinsic ordering. This structured discrimination problems allow for a novel scheme that provides a certified level of error, that is,…

Quantum Physics · Physics 2019-11-06 Esteban Martínez-Vargas , Ramon Munoz-Tapia

The quantum Zeno and anti-Zeno effects describe how frequent measurements can either suppress or accelerate quantum dynamics. While extensively studied in various platforms, their manifestation in dark-state dynamics remains largely…

We study the nonequilibrium stationary state (NESS) induced by quantum resetting of a system of $N$ noninteracting bosons in a harmonic trap. Our protocol consists of preparing initially the system in the ground state of a harmonic…

Quantum Gases · Physics 2025-03-13 Manas Kulkarni , Satya N. Majumdar , Sanjib Sabhapandit

This thesis deals with the generation, estimation and preservation of novel quantum states of two and three qubits, on an NMR quantum information processor. Using the maximum likelihood ansatz, we have developed a method for state…

Quantum Physics · Physics 2018-05-01 Harpreet Singh

Understanding the interplay between a quantum system and its environment lies at the heart of quantum science and its applications. To-date most efforts have focused on circumventing decoherence induced by the environment by either…