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Related papers: N-representability is QMA-complete

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Neural network quantum state (NNQS) has emerged as a promising candidate for quantum many-body problems, but its practical applications are often hindered by the high cost of sampling and local energy calculation. We develop a…

Quantum Physics · Physics 2023-11-02 Yangjun Wu , Chu Guo , Yi Fan , Pengyu Zhou , Honghui Shang

The reduced k-particle density matrix of a density matrix on finite-dimensional, fermion Fock space can be defined as the image under the orthogonal projection in the Hilbert-Schmidt geometry onto the space of k-body observables. A proper…

Mathematical Physics · Physics 2019-04-17 Volker Bach , Robert Rauch

Recently developed quantum algorithms suggest that quantum computers can solve certain problems and perform certain tasks more efficiently than conventional computers. Among other reasons, this is due to the possibility of creating…

Quantum Physics · Physics 2007-05-23 Rolando D. Somma

We show that the computational model based on local Fermionic modes in place of qubits does not satisfy local tomography and monogamy of entanglement, and has mixed states with maximal entanglement of formation. These features directly…

Quantum Physics · Physics 2014-07-28 Giacomo Mauro D'Ariano , Franco Manessi , Paolo Perinotti , Alessandro Tosini

The polynomial hierarchy plays a central role in classical complexity theory. Here, we define a quantum generalization of the polynomial hierarchy, and initiate its study. We show that not only are there natural complete problems for the…

Quantum Physics · Physics 2016-10-25 Sevag Gharibian , Julia Kempe

We formulate N-fold supersymmetry in quantum mechanical matrix models. As an example, we construct general two-by-two Hermitian matrix 2-fold supersymmetric quantum mechanical systems. We find that there are two inequivalent such systems,…

Mathematical Physics · Physics 2012-04-09 Toshiaki Tanaka

We develop a combinatorial approach to the quantum permutation algebras, as Hopf images of representations of type $\pi:A_s(n)\to B(H)$. We discuss several general problems, including the commutativity and cocommutativity ones, the…

Operator Algebras · Mathematics 2009-09-08 Teodor Banica , Julien Bichon , Jean-Marc Schlenker

The coherent superposition of non-orthogonal fermionic Gaussian states has been shown to be an efficient approximation to the ground states of quantum impurity problems [Bravyi and Gosset,Comm. Math. Phys.,356 451 (2017)]. We present a…

Strongly Correlated Electrons · Physics 2021-09-01 Samuel Boutin , Bela Bauer

We consider a twisted version of quantum groups corepresentations. This generalization amounts to include in the theory the case where quantum space coordinates and its endomorphism matrix entries belong to a non-commutative quadratic…

Quantum Algebra · Mathematics 2007-05-23 H. Montani , R. Trinchero

We consider the realization of universal quantum computation through braiding of Majorana fermions supplemented by unprotected preparation of noisy ancillae. It has been shown by Bravyi [Phys. Rev. A 73, 042313 (2006)] that under the…

Quantum Physics · Physics 2015-03-20 Fernando de Melo , Piotr Ćwikliński , Barbara M. Terhal

The paper is devoted to integral quantization, a procedure based on operator-valued measure and resolution of the identity. We insist on covariance properties in the important case where group representation theory is involved. We also…

Quantum Physics · Physics 2019-11-06 Jean Pierre Gazeau , Herve Bergeron

We prove classical simulation hardness, under the generalized $\mathsf{P}\neq\mathsf{NP}$ conjecture, for quantum circuit families with applications in near-term chemical ground state estimation. The proof exploits a connection to particle…

Quantum Physics · Physics 2026-02-06 Oskar Leimkuhler , K. Birgitta Whaley

The QMA-completeness of the local Hamiltonian problem is a landmark result of the field of Hamiltonian complexity that studies the computational complexity of problems in quantum many-body physics. Since its proposal, substantial effort has…

Quantum Physics · Physics 2026-02-11 Asad Raza , Jens Eisert , Alex B. Grilo

We present a deterministic optimization framework for Neural Network Quantum States (NQS) designed to bypass the sampling variance and slow mixing issues inherent in stochastic optimization. By projecting a neural backflow ansatz onto…

Chemical Physics · Physics 2026-05-12 Zheng Che

Continuous phase spaces have become a powerful tool for describing, analyzing, and tomographically reconstructing quantum states in quantum optics and beyond. A plethora of these phase-space techniques are known, however a thorough…

Quantum Physics · Physics 2020-02-24 Bálint Koczor , Robert Zeier , Steffen J. Glaser

Compressible models extend the domain of simulable systems in quantum computers, but little is known about their precise limits of applicability. Using the theory of compressible matchgate circuits, we identify a class of quadratic…

Quantum Physics · Physics 2022-07-29 Guillermo Blázquez-Cruz , Pierre-Luc Dallaire-Demers

It is a useful fact in classical computer science that many search problems are reducible to decision problems; this has led to decision problems being regarded as the $\textit{de facto}$ computational task to study in complexity theory. In…

Quantum Physics · Physics 2022-09-23 Sandy Irani , Anand Natarajan , Chinmay Nirkhe , Sujit Rao , Henry Yuen

In ab-initio electronic structure simulations, fermion-to-qubit mappings represent the initial encoding step of the fermionic problem into qubits. This work introduces a physically-inspired method for constructing mappings that…

Quantum computing has the potential to significantly speed up complex computational tasks, and arguably the most promising application area for near-term quantum computers is the simulation of quantum mechanics. To make the most of our…

Quantum Physics · Physics 2019-12-10 Sean A. Fischer , Daniel Gunlycke

Simulating molecules is believed to be one of the early-stage applications for quantum computers. Current state-of-the-art quantum computers are limited in size and coherence, therefore optimizing resources to execute quantum algorithms is…

Quantum Physics · Physics 2021-07-27 Kanav Setia , Richard Chen , Julia E. Rice , Antonio Mezzacapo , Marco Pistoia , James Whitfield