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We investigate how to experimentally detect a recently proposed measure to quantify macroscopic quantum superpositions [Phys. Rev. Lett. 106, 220401 (2011)], namely, "macroscopic quantumness" $\mathcal{I}$. Schemes based on overlap…

Quantum Physics · Physics 2017-01-17 Hyunseok Jeong , Changsuk Noh , Seunglee Bae , Dimitris G. Angelakis , Timothy C. Ralph

It is one of the most fundamental objectives in quantum information science to understand the boundary between the computational power of classical and quantum computers. One possible avenue to explore this boundary is to identify classes…

Quantum Physics · Physics 2025-03-28 Christophe Piveteau

The notion of compressed quantum computation is employed to simulate the Ising interaction of a 1D--chain consisting out of $n$ qubits using the universal IBM cloud quantum computer running on $\log(n)$ qubits. The external field parameter…

Quantum Physics · Physics 2017-05-24 M. Hebenstreit , D. Alsina , J. I. Latorre , B. Kraus

Classical shadow tomography has become a powerful tool in learning about quantum states prepared on a quantum computer. Recent works have used classical shadows to variationally enforce N-representability conditions on the 2-particle…

Quantum measurements play a fundamental role in quantum mechanics and quantum information processing, but it is not easy to implement generalized measurements, the most powerful measurements allowed by quantum mechanics. Here we propose a…

Quantum Physics · Physics 2019-07-02 Zihao Li , Haoyu Zhang , Huangjun Zhu

As quantum processing units (QPUs) scale toward hundreds of qubits, diagnosing noise-induced correlations (crosstalk) becomes critical for reliable quantum computation. In this work, we introduce Zero-Entropy Classical Shadows (ZECS), a…

Quantum technology has been rapidly growing due to its potential revolutionary applications. In particular, superconducting qubits provide a strong light-matter interaction as required for quantum computation and in principle can be scaled…

Quantum Physics · Physics 2019-04-23 Mahdi Naghiloo

We study classical shadows protocols based on randomized measurements in $n$-qubit entangled bases, generalizing the random Pauli measurement protocol ($n = 1$). We show that entangled measurements ($n\geq 2$) enable nontrivial and…

Quantum Physics · Physics 2024-03-27 Matteo Ippoliti

The Stochastic Series Expansion method (SSE) is a Quantum Monte Carlo (QMC) technique working directly in the imaginary time continuum and thus avoiding "Trotter discretization" errors. Using a non-local "operator-loop update" it allows…

Strongly Correlated Electrons · Physics 2007-05-23 A. Dorneich , M. Troyer

We review the progress and main challenges in implementing large-scale quantum computing by optical control of electron spins in quantum dots (QDs). Relevant systems include self-assembled QDs of III-V or II-VI compound semiconductors (such…

Quantum Physics · Physics 2010-09-13 Ren-Bao Liu , Wang Yao , L. J. Sham

We propose a scheme for a ground-code measurement-based quantum computer, which enjoys two major advantages. First, every logical qubit is encoded in the gapped degenerate ground subspace of a spin-1 chain with nearest-neighbor two-body…

Quantum Physics · Physics 2008-07-10 Gavin K. Brennen , Akimasa Miyake

Quantum simulation is a leading candidate for demonstrating practical quantum advantage over classical computation, as it is believed to provide exponentially more compute power than any classical system. It offers new means of studying the…

Quantum Physics · Physics 2026-01-23 Maja Franz , Lukas Schmidbauer , Joshua Ammermann , Ina Schaefer , Wolfgang Mauerer

We propose a system of equations to describe the interaction of a quasiclassical variable $X$ with a set of quantum variables $x$ that goes beyond the usual mean field approximation. The idea is to regard the quantum system as continuously…

Quantum Physics · Physics 2009-10-30 L. Diosi , J. J. Halliwell

Improving quantum algorithms run-time performance involves several strategies such as reducing the quantum gate counts, decreasing the number of measurements, advancement in QPU technology for faster gate operations, or optimizing the…

Quantum Physics · Physics 2025-07-31 Akhil Francis , Abhi D. Rajagopala , Norm M. Tubman , Katherine Klymko , Kasra Nowrouzi

Mapping quantum error correcting codes to classical disordered statistical mechanics models and studying the phase diagram of the latter has proven a powerful tool to study the fundamental error robustness and associated critical error…

Quantum Physics · Physics 2022-01-12 Davide Vodola , Manuel Rispler , Seyong Kim , Markus Müller

We present several refinements and extensions of the statistical quantum phase estimation (SQPE) framework to address some of its key practical limitations, improving its applicability to realistic cases. Recently, a family of statistical…

Quantum Physics · Physics 2026-05-20 Amit Surana , Brandon Allen

We combine classical heuristics with partial shadow tomography to enable efficient protocols for extracting information from correlated ab initio electronic systems encoded on quantum devices. By proposing the use of a correlation energy…

The development of emerging technologies in quantum optics demands accurate models that faithfully capture genuine quantum effects. Mature semiclassical approaches reach their limits when confronted with quantized electromagnetic fields,…

Quantum circuit complexity is a fundamental concept whose importance permeates quantum information, computation, many-body physics and high-energy physics. While extensively studied in closed systems, its characterization and behaviors in…

Quantum Physics · Physics 2025-08-28 Zhenyu Du , Zi-Wen Liu , Xiongfeng Ma

As a possible physical realization of a quantum information processor, a system with stacked self-assembled InAs quantum dots buried in GaAs in adjacent to the channel of a spin field-effect transistor has been proposed. In this system,…

Mesoscale and Nanoscale Physics · Physics 2009-03-19 Kazuya Yuasa , Kosuke Okano , Hiromichi Nakazato , Saori Kashiwada , Kanji Yoh