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It is generally considered that the signal output by a quantum circuit is attenuated exponentially fast in the number of gates. This letter explores how algorithms using mid-circuit measurements and classical conditioning as computational…

Quantum Physics · Physics 2024-01-05 Etienne Granet , Henrik Dreyer

We derive the theory of open quantum system dynamics intervened by a series of nonselective measurements. We analyze the cases of time independent and time dependent Hamiltonian dynamics in between the measurements and find the approximate…

Quantum Physics · Physics 2018-01-17 Sergey N. Filippov

Discovering quantum orders in mixed many-body systems is an ongoing issue. Very recently, the notion of an intrinsic mixed state topologically-ordered (IMTO) state was proposed. As a concrete example, we observe the emergence of IMTO by…

Quantum Physics · Physics 2025-05-06 Yoshihito Kuno , Takahiro Orito , Ikuo Ichinose

We propose a novel method to describe realistically ionization processes with absorbing boundary conditions in basis expansion within the formalism of the so-called Non-Adiabatic Quantum Molecular Dynamics. This theory couples…

Quantum Physics · Physics 2015-06-26 Mathias Uhlmann , Thomas Kunert , Ruediger Schmidt

Projective measurement, a basic operation in quantum mechanics, can induce seemingly nonlocal effects. In this work, we analyze such effects in many-body systems by studying the non-equilibrium dynamics of weakly monitored quantum circuits,…

Statistical Mechanics · Physics 2024-06-19 Shengqi Sang , Zhi Li , Timothy H. Hsieh , Beni Yoshida

Using the adiabatic perturbation theory of driven dynamics [Phys. Rev. A 78, 052508 (2008)] we design a hierarchy of quantum state preparation protocols that systematically increase the fidelity at very long driving times. We test these and…

Quantum Physics · Physics 2023-02-01 Felipe Matus , Jan Střeleček , Pavel Stránský , Pavel Cejnar

The paper introduces the application of information geometry to describe the ground states of Ising models by utilizing parity-check matrices of cyclic and quasi-cyclic codes on toric and spherical topologies. The approach establishes a…

Information Theory · Computer Science 2023-09-07 Vasiliy Usatyuk , Sergey Egorov , Denis Sapozhnikov

Quantifying and verifying the control level in preparing a quantum state are central challenges in building quantum devices. The quantum state is characterized from experimental measurements, using a procedure known as tomography, which…

Quantum Physics · Physics 2021-12-28 Quoc Hoan Tran , Kohei Nakajima

In the design of complex quantum systems like ion traps for quantum computing, it is usually desired to stabilize a particular system state or make the system state track a desired trajectory. Several control theoretical approaches based on…

Systems and Control · Computer Science 2012-11-26 K. P. Nagarjun , S. Sivaranjani , George Koshy

We consider a quantum system dynamics caused by successive selective and non-selective measurements of the probe coupled to the system. For the finite measurement rate $\tau^{-1}$ and the system-probe interaction strength $\gamma$ we derive…

Quantum Physics · Physics 2017-02-14 I. A. Luchnikov , S. N. Filippov

We are interested in dynamics of quantum many-body systems under continuous observation, and its physical realizations involving cold atoms in lattices. In the present work we focus on continuous measurement of atomic currents in lattice…

Quantum Physics · Physics 2017-05-23 C. Laflamme , D. Yang , P. Zoller

The hybrid approach to quantum computation simultaneously utilizes both discrete and continuous variables which offers the advantage of higher density encoding and processing powers for the same physical resources. Trapped ions, with…

Quantum Physics · Physics 2020-05-06 H. C. J. Gan , Gleb Maslennikov , Ko-Wei Tseng , Chihuan Nguyen , Dzmitry Matsukevich

Preparing algebraically correlated ground states of quantum many-body systems is an important, yet challenging task for quantum simulation. We introduce a protocol that employs local projective measurements and unitary feedback for…

Quantum Physics · Physics 2026-03-12 Johannes Feldmeier , Yu-Jie Liu , Mikhail D. Lukin , Soonwon Choi

Nonequilibrium dynamics of quantum many-body systems is challenging for classical computing, providing opportunities for demonstrating practical quantum computational advantage with analogue quantum simulators. Owing to the intimate…

We develop a classical shadow tomography protocol utilizing the randomized measurement scheme based on hybrid quantum circuits, which consist of layers of two-qubit random unitary gates mixed with single-qubit random projective…

Quantum Physics · Physics 2023-09-26 Ahmed A. Akhtar , Hong-Ye Hu , Yi-Zhuang You

Quantum entanglement is a particularly useful characterization of topological orders which lack conventional order parameters. In this work, we study the entanglement in topologically ordered states between two arbitrary spatial regions,…

Strongly Correlated Electrons · Physics 2023-08-01 Chao Yin , Shang Liu

In this article we reconsider a version of quantum trajectory theory based on the stochastic Schr\"odinger equation with stochastic coefficients, which was mathematically introduced in the '90s, and we develop it in order to describe the…

Quantum Physics · Physics 2012-10-30 Alberto Barchielli , Matteo Gregoratti

Measuring the temperature of a quantum system is an essential task in almost all aspects of quantum technologies. Theoretically, an optimal strategy for thermometry requires measuring energy which demands full accessibility over the entire…

Quantum Physics · Physics 2024-03-18 Yaoling Yang , Victor Montenegro , Abolfazl Bayat

We propose a unifying paradigm for analyzing and constructing topological quantum error correcting codes as dynamical circuits of geometrically local channels and measurements. To this end, we relate such circuits to discrete fixed-point…

Quantum Physics · Physics 2024-03-27 Andreas Bauer

Decoherence is a major obstacle to the preparation of topological order in noisy intermediate-scale quantum devices. Here, we show that decoherence can also give rise to new types of topological order. Specifically, we construct concrete…

Quantum Physics · Physics 2025-01-23 Zijian Wang , Zhengzhi Wu , Zhong Wang