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Physical Gottesman-Kitaev-Preskill (GKP) states are inherently noisy as ideal ones would require infinite energy. While this is typically considered as a deficiency to be actively corrected, this work demonstrates that imperfect GKP…

Quantum Physics · Physics 2026-03-12 Fariba Hosseinynejad , Pavithran Iyer , Guillaume Dauphinais , David L. Feder

We show how to optimally reduce the local Hilbert basis of lattice quantum many-body (QMB) Hamiltonians. The basis truncation exploits the most relevant eigenvalues of the estimated single-site reduced density matrix (RDM). It is accurate…

Strongly Correlated Electrons · Physics 2025-09-23 Peter Majcen , Giovanni Cataldi , Pietro Silvi , Simone Montangero

Quantum state preparation (QSP) is a fundamental task in quantum computing and quantum information processing. It is critical to the execution of many quantum algorithms, including those in quantum machine learning. In this paper, we…

Data Structures and Algorithms · Computer Science 2025-08-01 Xin Hong , Aochu Dai , Chenjian Li , Sanjiang Li , Shenggang Ying , Mingsheng Ying

Product states, unentangled tensor products of single qubits, are a ubiquitous ansatz in quantum computation, including for state-of-the-art Hamiltonian approximation algorithms. A natural question is whether we should expect to efficiently…

Quantum Physics · Physics 2025-02-12 John Kallaugher , Ojas Parekh , Kevin Thompson , Yipu Wang , Justin Yirka

Recent work has explored using the stabilizer formalism to classically simulate quantum circuits containing a few non-Clifford gates. The computational cost of such methods is directly related to the notion of stabilizer rank, which for a…

Quantum Physics · Physics 2019-09-04 Sergey Bravyi , Dan Browne , Padraic Calpin , Earl Campbell , David Gosset , Mark Howard

We present an efficient protocol leveraging classical computation to support Initial State Preparation for strongly correlated fermionic systems, a critical bottleneck for fault-tolerant quantum simulation. Focusing on nuclear shell model…

Quantum Physics · Physics 2026-03-27 Joe Gibbs , Lukasz Cincio , Chandan Sarma , Zoë Holmes , Paul Stevenson

Quantum Hamiltonian complexity studies computational complexity aspects of local Hamiltonians and ground states; these questions can be viewed as generalizations of classical computational complexity problems related to local constraint…

Quantum Physics · Physics 2015-03-17 Dorit Aharonov , Itai Arad , Zeph Landau , Umesh Vazirani

QMA and QCMA are possible quantum analogues of the complexity class NP. In QCMA the verifier is a quantum program and the proof is classical. In contrast, in QMA the proof is also a quantum state. We show that two known QMA-complete…

Quantum Physics · Physics 2007-05-23 Pawel Wocjan , Dominik Janzing , Thomas Beth

We show that it is possible to uniquely reconstruct a generic many-body local Hamiltonian from a single pair of initial and final states related by time evolution with the Hamiltonian. We then propose a practical version of the protocol…

Quantum Physics · Physics 2020-04-28 Zhi Li , Liujun Zou , Timothy H. Hsieh

The Local Hamiltonian problem (finding the ground state energy of a quantum system) is known to be QMA-complete. The Local Consistency problem (deciding whether descriptions of small pieces of a quantum system are consistent) is also known…

Quantum Physics · Physics 2007-12-17 Yi-Kai Liu

In a model of fault-tolerant quantum computation with quick and noiseless polyloglog-time auxiliary classical computation, we construct a fault tolerance protocol with constant-space and $\widetilde{O}(\log N)$-time overhead, where…

Quantum Physics · Physics 2025-08-15 Quynh T. Nguyen , Christopher A. Pattison

As quantum computing resources remain scarce and error rates high, minimizing the resource consumption of quantum circuits is essential for achieving practical quantum advantage. Here we consider the natural problem of, given a circuit $C$,…

Quantum Physics · Physics 2026-02-27 Adam Husted Kjelstrøm , Andreas Pavlogiannis , Jaco van de Pol

The postulate of gauge invariance in nature does not lend itself directly to implementations of lattice gauge theories in modern setups of quantum synthetic matter. Unavoidable gauge-breaking errors in such devices require gauge invariance…

We study a non-stabilizerness resource theory for operators, which is dual to that describing states. We identify that the stabilizer R\'enyi entropy analog in operator space is a good magic monotone satisfying the usual conditions while…

Quantum Physics · Physics 2025-08-26 Neil Dowling , Pavel Kos , Xhek Turkeshi

We formulate a simple condition for reconstructibility of a certain class of Hamiltonians with real potentials from the knowledge of their complex-valued eigenfunctions. This may be relevant to the question of preparability of quantum…

Quantum Physics · Physics 2017-04-13 Andrei Galiautdinov

The low-temperature physics of quantum many-body systems is largely governed by the structure of their ground states. Minimizing the energy of local interactions, ground states often reflect strong properties of locality such as the area…

Quantum Physics · Physics 2017-01-18 Tomotaka Kuwahara , Itai Arad , Luigi Amico , Vlatko Vedral

Efficient block encoding of many-body Hamiltonians is a central requirement for quantum algorithms in scientific computing, particularly in the early fault-tolerant era. In this work, we introduce new explicit constructions for block…

Quantum Physics · Physics 2025-10-13 Diyi Liu , Shuchen Zhu , Guang Hao Low , Lin Lin , Chao Yang

Within the framework of nonrelativisitic quantum electrodynamics we consider a single nucleus and $N$ electrons coupled to the radiation field. Since the total momentum $P$ is conserved, the Hamiltonian $H$ admits a fiber decomposition with…

Mathematical Physics · Physics 2007-05-23 Michael Loss , Tadahiro Miyao , Herbert Spohn

Stabilizer states, which are also known as the Clifford states, have been commonly utilized in quantum information, quantum error correction, and quantum circuit simulation due to their simple mathematical structure. In this work, we apply…

Quantum Physics · Physics 2025-06-26 Jiace Sun , Lixue Cheng , Shi-Xin Zhang

We study the task of agnostic tomography: given copies of an unknown $n$-qubit state $\rho$ which has fidelity $\tau$ with some state in a given class $C$, find a state which has fidelity $\ge \tau - \epsilon$ with $\rho$. We give a new…

Quantum Physics · Physics 2024-12-06 Sitan Chen , Weiyuan Gong , Qi Ye , Zhihan Zhang