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In analogy with conventional quantum mechanics, non-commutative quantum mechanics is formulated as a quantum system on the Hilbert space of Hilbert-Schmidt operators acting on non-commutative configuration space. It is argued that the…

Mathematical Physics · Physics 2009-04-17 F G Scholtz , L Gouba , A Hafver , C M Rohwer

We propose a technique to design control algorithms for a class of finite dimensional quantum systems so that the control law does not present discontinuities. The class of models considered admits a group of symmetries which allows us to…

Quantum Physics · Physics 2019-10-23 Domenico D'Alessandro , Benjamin Sheller

We study a non-interacting quantum particle, moving on a one-dimensional lattice, which is subjected to repetitive measurements. We investigate the consequence when such motion is interrupted and restarted from the same initial…

Quantum Physics · Physics 2023-03-21 Ranjan Modak , S. Aravinda

We present control schemes for open quantum systems that combine decoupling and universal control methods with coding procedures. By exploiting a general algebraic approach, we show how appropriate encodings of quantum states result in…

Quantum Physics · Physics 2009-11-06 Lorenza Viola , Emanuel Knill , Seth Lloyd

The dynamics of open quantum systems is determined by avoided and true crossings of eigenvalue trajectories of a non-Hermitian Hamiltonian. The phases of the eigenfunctions are not rigid so that environmentally induced spectroscopic…

Quantum Physics · Physics 2009-09-28 Ingrid Rotter

Advances in topological photonics and non-Hermitian optics have drastically changed our perception on how interdisciplinary concepts may empower unprecedented applications. Bridging the two areas could uncover the reciprocity between…

Heisenberg spin chains can act as quantum wires transferring quantum states either perfectly or with high fidelity. Gaussian packets of excitations passing through dual rails can encode the two states of a logical qubit, depending on which…

Quantum Physics · Physics 2016-07-06 Sahand Seifnashri , Farzad Keyanvash , Jahangir Nobakht , Vahid Karimipour

For a quantum system governed by a non-Hermitian Hamiltonian, we studied the problem of obtaining an optimum Hamiltonian that generates nonunitary transformations of a given initial state into a certain final state in the smallest time…

Quantum Physics · Physics 2012-11-15 Alexander I Nesterov

In this study, we address the challenge of controlling quantum systems under environmental influences using the theory of dynamical invariants. We employ a reverse engineering approach to develop control protocols designed to be robust…

Quantum Physics · Physics 2024-08-20 Loris Maria Cangemi , Hilario Espinós , Ricardo Puebla , Erik Torrontegui , Amikam Levy

We demonstrate that genuinely non-Hermitian topological phases and corresponding topological phase transitions can be naturally realized in monitored quantum circuits, exemplified by the paradigmatic non-Hermitian Su-Schrieffer-Heeger…

Mesoscale and Nanoscale Physics · Physics 2022-08-26 Christoph Fleckenstein , Alberto Zorzato , Daniel Varjas , Emil J. Bergholtz , Jens H. Bardarson , Apoorv Tiwari

There exist instances of dynamical systems possessing symmetry transformations of which the conserved Noether charges generating these symmetries feature an explicit time dependence in their functional representation over phase space. The…

High Energy Physics - Theory · Physics 2019-07-02 Jan Govaerts

A non-commuting measurement transfers, via the apparatus, information encoded in a system's state to the external "observer". Classical measurements determine properties of physical objects. In the quantum realm, the very same notion…

Quantum Physics · Physics 2016-08-31 Bartłomiej Gardas , Sebastian Deffner , Avadh Saxena

Quantum control plays a crucial role in enhancing precision scaling for quantum sensing. However, most existing protocols require perfect control, even though real-world devices inevitably have control imperfections. Here, we consider a…

Quantum Physics · Physics 2025-12-09 Zi-Shen Li , Xinyue Long , Xiaodong Yang , Dawei Lu , Yuxiang Yang

The quantum harmonic oscillator with parity-time ($\mathcal{PT}$) symmetry, obtained from the ordinary (Hermitian) quantum harmonic oscillator by an imaginary displacement of the spatial coordinate, provides an important and…

Quantum Physics · Physics 2016-11-23 Stefano Longhi

Quantum metrology leverages quantum resources such as entanglement and squeezing to enhance parameter estimation precision beyond classical limits. While optimal quantum control strategies can assist to reach or even surpass the Heisenberg…

Quantum Physics · Physics 2025-10-17 Qifei Wei , Shengshi Pang

It has been argued that it is incompatible to maintain unitary time-evolution for time-dependent non-Hermitian Hamiltonians when the metric operator is explicitly time-dependent. We demonstrate here that the time-dependent Dyson equation…

Quantum Physics · Physics 2016-04-27 Andreas Fring , Miled H. Y. Moussa

The ability to accurately control a quantum system is a fundamental requirement in many areas of modern science such as quantum information processing and the coherent manipulation of molecular systems. It is usually necessary to realize…

Non-Hermitian systems have garnered significant attention due to the emergence of novel topology of complex spectra and skin modes. However, investigating transport phenomena in such systems faces obstacles stemming from the non-unitary…

Mesoscale and Nanoscale Physics · Physics 2023-11-16 Qing Yan , Hailong Li , Qing-Feng Sun , X. C. Xie

We consider the problem of time optimal control of a continuous bosonic quantum system subject to the action of a Markovian dissipation. In particular, we consider the case of a one mode Gaussian quantum system prepared in an arbitrary…

Quantum Physics · Physics 2014-12-01 Alberto Carlini , Andrea Mari , Vittorio Giovannetti

The goal of the present account is to review our efforts to obtain and apply a ``collective'' Hamiltonian for a few, approximately decoupled, adiabatic degrees of freedom, starting from a Hamiltonian system with more or many more degrees of…

Nuclear Theory · Physics 2009-09-25 G. Do Dang , A. Klein , N. R. Walet