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Memory is an indispensable component in classical computing systems. While the development of quantum computing is still in its early stages, current quantum processing units mainly function as quantum registers. Consequently, the actual…

Quantum Physics · Physics 2023-11-06 Chenxu Liu , Meng Wang , Samuel A. Stein , Yufei Ding , Ang Li

It is well known in the realm of quantum mechanics and information theory that the entropy is non-decreasing for the class of unital physical processes. However, in general, the entropy does not exhibit monotonic behavior. This has…

Quantum Physics · Physics 2018-01-31 Siddhartha Das , Sumeet Khatri , George Siopsis , Mark M. Wilde

Quantum memories are an important building block for quantum information processing. Ideally, these memories preserve the quantum properties of the input. We present general criteria for measures to evaluate the quality of quantum memories.…

Quantum Physics · Physics 2019-06-19 Timo Simnacher , Nikolai Wyderka , Cornelia Spee , Xiao-Dong Yu , Otfried Gühne

The behavior of quantum states at exceptional points and at critical points associated with quantum phase transitions is intriguing yet puzzling. In this study, we present an alternative method for obtaining the Berry potentials using the…

Quantum Physics · Physics 2025-11-18 Chia-Yi Ju , Fu-Hsiang Huang

Measurements of quantum systems can be used to generate classical data that is truly unpredictable for every observer. However, this true randomness needs to be discriminated from randomness due to ignorance or lack of control of the…

Quantum Physics · Physics 2017-06-14 Felix Bischof , Hermann Kampermann , Dagmar Bruß

The theoretical description of quantum dynamics in an intriguing way does not necessarily imply the underlying dynamics is indeed intriguing. Here we show how a known very interesting master equation with an always negative decay rate…

Quantum Physics · Physics 2017-07-31 Nina Megier , Dariusz Chruściński , Jyrki Piilo , Walter T. Strunz

Quantum computers have the opportunity to be transformative for a variety of computational tasks. Recently, there have been proposals to use the unsimulatably of large quantum devices to perform regression, classification, and other machine…

Quantum kernel methods promise enhanced expressivity for learning structured data, but their usefulness has been limited by kernel concentration and barren plateaus. Both effects are mathematically equivalent and suppress trainability. We…

Quantum computers promise to enhance machine learning for practical applications. Quantum machine learning for real-world data has to handle extensive amounts of high-dimensional data. However, conventional methods for measuring quantum…

Quantum Physics · Physics 2023-02-10 Tobias Haug , Chris N. Self , M. S. Kim

We construct a gate and time-independent noise model that results in the output of a logical randomized benchmarking protocol oscillating rather than decaying exponentially. To illustrate our idea, we first construct an example in standard…

Quantum Physics · Physics 2022-12-13 Athena Ceasura , Pavithran Iyer , Joel J. Wallman , Hakop Pashayan

We demonstrate characterizing quantum evolutions via matrix factorization algorithm, a particular type of the recommender system (RS). A system undergoing a quantum evolution can be characterized in several ways. Here we choose (i) quantum…

Quantum Physics · Physics 2021-12-08 Priya Batra , Anukriti Singh , T. S. Mahesh

Random access memory is an indispensable device for classical information technology. Analog to this, for quantum information technology, it is desirable to have a random access quantum memory with many memory cells and programmable access…

Quantum Physics · Physics 2019-04-25 N. Jiang , Y. -F. Pu , W. Chang , C. Li , S. Zhang , L. -M. Duan

The dynamics of open quantum systems and manipulation of quantum resources are both of fundamental interest in quantum physics. Here, we investigate the relation between quantum Markovianity and coherence, providing an effective way for…

Quantum Physics · Physics 2020-06-23 Kang-Da Wu , Zhibo Hou , Guo-Yong Xiang , Chuan-Feng Li , Guang-Can Guo , Daoyi Dong , Franco Nori

Recent developments have led to the possibility of embedding machine learning tools into experimental platforms to address key problems, including the characterization of the properties of quantum states. Leveraging on this, we implement a…

The concept of quantum complexity has far-reaching implications spanning theoretical computer science, quantum many-body physics, and high energy physics. The quantum complexity of a unitary transformation or quantum state is defined as the…

High Energy Physics - Theory · Physics 2021-08-02 Fernando G. S. L. Brandão , Wissam Chemissany , Nicholas Hunter-Jones , Richard Kueng , John Preskill

We consider the problem of an electron tunneling between two coupled quantum dots, a two-state quantum system (qubit), using a low-transparency point contact (PC) or tunnel junction as a detector continually measuring the position of the…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 Hsi-Sheng Goan , Gerard J. Milburn

Quantum computers are important examples of processes whose evolution can be described in terms of iterations of single step operators or their adjoints. Based on this, Hamiltonian evolution of processes with associated step operators $T$…

Quantum Physics · Physics 2009-10-30 Paul Benioff

Variational quantum circuits build the foundation for various classes of quantum algorithms. In a nutshell, the weights of a parametrized quantum circuit are varied until the empirical sampling distribution of the circuit is sufficiently…

A quantum system will stay near its instantaneous ground state if the Hamiltonian that governs its evolution varies slowly enough. This quantum adiabatic behavior is the basis of a new class of algorithms for quantum computing. We test one…

Quantum Physics · Physics 2009-11-07 Edward Farhi , Jeffrey Goldstone , Sam Gutmann , Joshua Lapan , Andrew Lundgren , Daniel Preda

Logical qubits encoded in quantum error correcting codes can exhibit non-Markovian dynamical evolution, even when the underlying physical noise is Markovian. To understand this emergent non-Markovianity, we define a Markovianity condition…

Quantum Physics · Physics 2026-02-23 Jalan A. Ziyad , Robin Blume-Kohout , Kenneth Rudinger