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We show that Gallager's ensemble of Low-Density Parity Check (LDPC) codes achieves list-decoding capacity with high probability. These are the first graph-based codes shown to have this property. This result opens up a potential avenue…

Information Theory · Computer Science 2024-07-11 Jonathan Mosheiff , Nicolas Resch , Noga Ron-Zewi , Shashwat Silas , Mary Wootters

It has long been known that long-ranged entangled topological phases can be exploited to protect quantum information against unwanted local errors. Indeed, conditions for intrinsic topological order are reminiscent of criteria for faithful…

Quantum Physics · Physics 2021-02-18 Julio Carlos Magdalena de la Fuente , Nicolas Tarantino , Jens Eisert

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 construct a class of exact ground states for correlated electrons on pentagon chains in the high density region and discuss their physical properties. In this procedure the Hamiltonian is first cast in a positive semidefinite form using…

Strongly Correlated Electrons · Physics 2013-05-27 Zsolt Gulacsi

Low-density parity-check (LDPC) codes have been the subject of much interest due to the fact that they can perform near the Shannon limit. In this paper we present a construction of LDPC codes from cubic symmetric graphs. The constructed…

Combinatorics · Mathematics 2020-02-18 Dean Crnkovic , Sanja Rukavina , Marina Simac

The robustness of topological properties, such as quantized currents, generally depends on the existence of gaps surrounding the relevant energy levels or on symmetry-forbidden transitions. Here, we observe quantized currents that survive…

Mesoscale and Nanoscale Physics · Physics 2025-08-21 Emmanuel Gottlob , Dan S. Borgnia , Robert-Jan Slager , Ulrich Schneider

With recent breakthroughs in the construction of good qLDPC codes and nearly good qLTCs, the study of (co)homological invariants of quantum code complexes, which fundamentally underlie their logical operations, has become evidently…

Quantum Physics · Physics 2026-03-30 Zimu Li , Yuguo Shao , Fuchuan Wei , Yiming Li , Zi-Wen Liu

We develop a stability theory for contractive local IFSs on compact metric spaces. Unlike the classical global setting, local systems may exhibit a richer symbolic and geometric structure, including code spaces that are not of finite type…

Dynamical Systems · Mathematics 2026-05-05 Elismar R. Oliveira , Paulo Varandas

We present analytical and numerical studies of the behaviour of the $\alpha$-Renyi entropies in the Toric code in presence of several types of perturbations aimed at studying the simulability of these perturbations to the parent Hamiltonian…

Quantum Physics · Physics 2015-01-14 Siddhartha Santra , Alioscia Hamma , Lukasz Cincio , Yigit Subasi , Paolo Zanardi , Luigi Amico

The stability of periodic traveling wave solutions to dispersive PDEs with respect to `arbitrary' perturbations is still widely open. The focus is put here on stability with respect to perturbations of the same period as the wave, for…

Analysis of PDEs · Mathematics 2016-09-21 Sylvie Benzoni-Gavage , Colin Mietka , L. Miguel Rodrigues

We establish a sharp criterion for the stability of a class of compactly supported, homogeneous density``minimal compact solitons'' or MCS states, of the time-dependent discrete nonlinear Schr\"odinger equation on a multi-lattice, $\mathbb…

Pattern Formation and Solitons · Physics 2025-11-27 Cheng Shi , Ross Parker , Panayotis G. Kevrekides , Michael I. Weinstein

We establish an important duality correspondence between topological order in quantum many body systems and criticality in ferromagnetic classical spin systems. We show how such a correspondence leads to a classical and simple procedure for…

Quantum Physics · Physics 2020-05-20 Mohammad Hossein Zarei , Afshin Montakhab

In this paper, we construct protograph-based spatially coupled low-density parity-check (SC-LDPC) codes by coupling together a series of L disjoint, or uncoupled, LDPC code Tanner graphs into a single coupled chain. By varying L, we obtain…

Information Theory · Computer Science 2016-11-17 David G. M. Mitchell , Michael Lentmaier , Daniel J. Costello

We consider the cubic Schr\"odinger equation on the euclidean space perturbed by a short-range potential $V$. The presence of a negative simple eigenvalue for $-\Delta+V$ gives rise to a curve of small and localized nonlinear ground states…

Analysis of PDEs · Mathematics 2021-09-14 Nicolas Camps

Consider a linear autonomous Hamiltonian system with a time periodic bound state solution. In this paper we study the structural instability of this bound state ^M relative to time almost periodic perturbations which are small, localized…

Pattern Formation and Solitons · Physics 2009-09-25 Eduard Kirr , Michael I. Weinstein

The $k$-local Hamiltonian problem is a central model for quantum many-body systems and Hamiltonian complexity. Semidefinite programming and noncommutative sum-of-squares hierarchies provide systematic certificates for ground-state energies,…

Quantum Physics · Physics 2026-05-29 Igor Klep , Nando Leijenhorst , Victor Magron

We have studied the extended Hubbard model with pair hopping in the atomic limit for arbitrary electron density and chemical potential. The Hamiltonian considered consists of (i) the effective on-site interaction U and (ii) the intersite…

Strongly Correlated Electrons · Physics 2012-05-01 Konrad Kapcia , Stanisław Robaszkiewicz , Roman Micnas

We investigate whether a generic multipartite pure state can be the unique asymptotic steady state of locality-constrained purely dissipative Markovian dynamics. In the simplest tripartite setting, we show that the problem is equivalent to…

Quantum Physics · Physics 2018-04-04 Salini Karuvade , Peter D. Johnson , Francesco Ticozzi , Lorenza Viola

A Hamiltonian density bounded from below implies that the lowest-energy state is stable. We point out, contrary to common lore, that an unbounded Hamiltonian density does not necessarily imply an instability: Stability is indeed a…

General Relativity and Quantum Cosmology · Physics 2018-12-12 Eugeny Babichev , Christos Charmousis , Gilles Esposito-Farese , Antoine Lehébel

Recent constructions of quantum low-density parity-check (QLDPC) codes provide optimal scaling of the number of logical qubits and the minimum distance in terms of the code length, thereby opening the door to fault-tolerant quantum systems…

Quantum Physics · Physics 2024-01-24 Narayanan Rengaswamy , Nithin Raveendran , Ankur Raina , Bane Vasić