Publications

Order by: publication date number of citations

Three-dimensional quantum Hall effect in topological amorphous metals

Jiong-Hao Wang, Yong Xu

SciPost Phys. 18, 146 (2025) · published 2 May 2025 | · pdf

Weyl semimetals have been theoretically predicted to become topological metals with anomalous Hall conductivity in amorphous systems. However, measuring the anomalous Hall conductivity in realistic materials, particularly those with multiple pairs of Weyl points, is a significant challenge. If a system respects time-reversal symmetry, then the anomalous Hall conductivity even vanishes. As such, it remains an open question how to probe the Weyl band like topology in amorphous materials. Here, we theoretically demonstrate that, under magnetic fields, a topological metal slab in amorphous systems exhibits three-dimensional quantum Hall effect, even in time-reversal invariant systems, thereby providing a feasible approach to exploring Weyl band like topology in amorphous materials. We unveil the topological origin of the quantized Hall conductance by calculating the Bott index. The index is carried by broadened Landau levels with bulk states spatially localized except at critical transition energies. The topological property also results in edge states localized at distinct hinges on two opposite surfaces.
Single-particle spectra and magnetic susceptibility in the Emery model: A dynamical mean-field perspective

Yi-Ting Tseng, Mário O. Malcolms, Henri Menke, Marcel Klett, Thomas Schäfer, Philipp Hansmann

SciPost Phys. 18, 145 (2025) · published 1 May 2025 | · pdf

We investigate dynamical mean-field calculations of the three-band Emery model at the one- and two-particle level for material-realistic parameters of high-$T_c$ superconductors. Our study shows that even within dynamical mean-field theory, which accounts solely for temporal fluctuations, the intrinsic multi-orbital nature of the Emery model introduces effective non-local correlations. These correlations lead to a non-Curie-like temperature dependence of the magnetic susceptibility, consistent with nuclear magnetic resonance experiments in the pseudogap regime. By analyzing the temperature dependence of the uniform static spin susceptibility obtained by single-site and cluster dynamical mean-field theory, we find indications of emerging oxygen-copper singlet fluctuations, explicitly captured by the model. Despite correctly describing the hallmark of the pseudogap at the two-particle level, such as the drop in the Knight shift of nuclear magnetic resonance, dynamical mean-field theory fails to capture the spectral properties of the pseudogap.
Quantum analytic Langlands correspondence

Davide Gaiotto, Jörg Teschner

SciPost Phys. 18, 144 (2025) · published 30 April 2025 | · pdf

The analytic Langlands correspondence describes the solution to the spectral problem for the quantised Hitchin Hamiltonians. It is related to the S-duality of $\mathcal{N}=4$ super Yang-Mills theory. We propose a one-parameter deformation of the Analytic Langlands Correspondence, and discuss its relations to quantum field theory. The partition functions of the $H_3^+$ WZNW model are interpreted as the wave-functions of a spherical vector in the quantisation of complex Chern-Simons theory. Verlinde line operators generate a representation of two copies of the quantised skein algebra on generalised partition functions. We conjecture that this action generates a basis for the underlying Hilbert space, and explain in which sense the resulting quantum theory represents a deformation of the Analytic Langlands Correspondence.
Thermalization of the quantum planar rotor with external potential

Birthe Schrinski, Yoon Jun Chan, Björn Schrinski

SciPost Phys. Core 8, 040 (2025) · published 30 April 2025 | · pdf

We study decoherence, diffusion, friction, and how they thermalize a planar rotor in the presence of an external potential. Representing the quantum master equation in terms of auxiliary Wigner functions in periodic phase space not only illustrates the thermalization process in a concise way, but also allows for an efficient numerical evaluation of the open quantum dynamics and its approximate analytical description. In particular, we analytically and numerically verify the existence of a steady state that, in the high-temperature regime, closely approximates a Gibbs state. We also derive the proper classical limit of the planar rotor time evolution and present exemplary numerical studies to verify our results.
Crystals and double quiver algebras from Jeffrey-Kirwan residues

Jiakang Bao, Masahito Yamazaki

SciPost Phys. 18, 143 (2025) · published 29 April 2025 | · pdf

We construct statistical mechanical models of crystal melting describing the flavoured Witten indices of $\mathcal{N}≥ 2$ supersymmetric quiver gauge theories. Our results can be derived from the Jeffrey-Kirwan (JK) residue formulas, and generalize the previous results for quivers corresponding to toric Calabi-Yau threefolds and fourfolds to a large class of quivers satisfying the no-overlap condition, including those corresponding to some non-toric Calabi-Yau manifolds. We construct new quiver algebras which we call the double quiver Yangians/algebras, as well as their representations in terms of the aforementioned crystals. For theories with four supercharges, we compare the double quiver algebras with the existing quiver Yangians/BPS algebras, which we show can also be constructed from the JK residues. For theories with two supercharges, the double quiver algebras provide an algebraic description of the BPS states, including the information of the fixed points and their relative coefficients in the full partition functions.
Self-congruent point in critical matrix product states: An effective field theory for finite-entanglement scaling

Jan T. Schneider, Atsushi Ueda, Yifan Liu, Andreas M. Läuchli, Masaki Oshikawa, Luca Tagliacozzo

SciPost Phys. 18, 142 (2025) · published 29 April 2025 | · pdf

We set up an effective field theory formulation for the renormalization flow of matrix product states (MPS) with finite bond dimension, focusing on systems exhibiting finite-entanglement scaling close to a conformally invariant critical fixed point. We show that the finite MPS bond dimension $\chi$ is equivalent to introducing a perturbation by a relevant operator to the fixed-point Hamiltonian. The fingerprint of this mechanism is encoded in the $\chi$-independent universal transfer matrix's gap ratios, which are distinct from those predicted by the unperturbed Conformal Field Theory (CFT). This phenomenon defines a renormalization group self-congruent point, where the relevant coupling constant ceases to flow due to a balance of two effects; When increasing $\chi$, the infrared scale, set by the correlation length $\xi(\chi)$, increases, while the strength of the perturbation at the lattice scale decreases. The presence of a self-congruent point does not alter the validity of the finite-entanglement scaling hypothesis, since the self-congruent point is located at a finite distance from the critical fixed point, well inside the scaling regime of the CFT. We corroborate this framework with numerical evidence from the exact solution of the Ising model and density matrix renormalization group (DMRG) simulations of an effective lattice model.
Non-topological edge-localized Yu-Shiba-Rusinov states in CrBr$_3$/NbSe$_2$ heterostructures

Jan P. Cuperus, Daniel Vanmaekelbergh, Ingmar Swart

SciPost Phys. 18, 141 (2025) · published 28 April 2025 | · pdf

Topological superconductivity is predicted to emerge in certain magnet-superconductor hybrid systems. Here, we revisit the heterostructure of insulating monolayer CrBr$_{3}$ and NbSe$_{2}$, for which different conclusions on the presence of topological superconductivity have been reported. Using low-temperature scanning tunneling microscopy and (shot noise) spectroscopy, we find that the superconducting gap well inside the CrBr$_{3}$ islands is not affected by magnetism. At the island edges, we observe Yu-Shiba-Rusinov (YSR) states at a variety of in-gap positions, including zero energy. The absence of topological superconductivity is verified by extensive dI/dV measurements at the CrBr$_{3}$ island edges. Our results ask for a more detailed understanding of the interaction between magnetic insulators and superconductors.
Two portals to GeV sterile neutrinos: Dipole versus mixing

Enrico Bertuzzo, Michele Frigerio

SciPost Phys. 18, 140 (2025) · published 28 April 2025 | · pdf

Massive sterile neutrinos, also known as heavy neutral leptons, can have a mixing with active neutrinos, $\theta$, as well as a dipole coupling to the photon, $d$. We study the interplay between these two portals, considering the production from meson decays of sterile neutrinos with mass $0.1$ GeV $≲ M_N ≲ 10$ GeV, at beam-dump facilities such as NA62 and SHiP, and at the FASER2 experiment. These sterile neutrinos can be long-lived and decay into a photon in a distant detector, via the dipole operator. We find that all these experiments will be sensitive to values of $d$ which are presently unconstrained. The experimental reach varies strongly with the mass $M_N$ and the mixing $\theta$, and one observes specific correlations with the flavour of active neutrinos. The SHiP experiment will mark a jump in sensitivity: (i) it will probe a sterile dipole as small as $d\sim 10^{-8}\ \text{GeV}^{-1}$, thus testing new physics well above the electroweak scale; (ii) it may detect the active-sterile dipole to the level predicted by electroweak loops, if $\theta$ is close to the present bound.
Identifying the quantum properties of hadronic resonances using machine learning

Jakub Filipek, Shih-Chieh Hsu, John Kruper, Kirtimaan Mohan, Benjamin Nachman

SciPost Phys. Core 8, 039 (2025) · published 28 April 2025 | · pdf

With the great promise of deep learning, discoveries of new particles at the Large Hadron Collider (LHC) may be imminent. Following the discovery of a new Beyond the Standard model particle in an all-hadronic channel, deep learning can also be used to identify its quantum numbers. Convolutional neural networks (CNNs) using jet-images can significantly improve upon existing techniques to identify the quantum chromodynamic (QCD) ('color') as well as the spin of a two-prong resonance using its substructure. Additionally, jet-images are useful in determining what information in the jet radiation pattern is useful for classification, which could inspire future taggers. These techniques improve the categorization of new particles and are an important addition to the growing jet substructure toolkit, for searches and measurements at the LHC now and in the future.
Integrable models on Rydberg atom chains

Luke Corcoran, Marius de Leeuw, Balázs Pozsgay

SciPost Phys. 18, 139 (2025) · published 25 April 2025 | · pdf

We initiate a systematic study of integrable models for spin chains with constrained Hilbert spaces; we focus on spin-1/2 chains with the Rydberg constraint. We extend earlier results for medium-range spin chains to the constrained Hilbert space, and formulate an integrability condition. This enables us to construct new integrable models with fixed interaction ranges. We classify all time- and space-reflection symmetric integrable Rydberg-constrained Hamiltonians of range 3 and 4. At range 3, we find a single family of integrable Hamiltonians: the so-called RSOS quantum chains, which are related to the well-known RSOS models of Andrews, Baxter, and Forrester. At range 4 we find two families of models, the first of which is the constrained XXZ model. We also find a new family of models depending on a single coupling $z$. We provide evidence of two critical points related to the golden ratio $\phi$, at $z=\phi^{-1/2}$ and $z=\phi^{3/2}$. We also perform a partial classification of integrable Hamiltonians for range 5.

Previous 1 2 3 4 5 6 7 8 9 10 ... 328 Next