Publications

Order by: publication date number of citations

• A quantum theory of the nearly frozen charge glass

  Simone Fratini, Katherine Driscoll, Sergio Ciuchi, Arnaud Ralko

  SciPost Phys. 14, 124 (2023) · published 23 May 2023 | Toggle abstract · pdf

  We study long-range interacting electrons on the triangular lattice using mixed quantum/classical simulations going beyond the usual classical descriptions of the lattice Coulomb fluid. Our results in the strong interaction limit indicate that the proliferation of quantum defects governs the low-temperature dynamics of this strongly frustrated system. The present theoretical findings explain the phenomenology observed in the $\theta$-ET$_2$X materials as they fall out of equilibrium, including glassiness, resistive switching and a strong sensitivity to the electronic structure anisotropy. The method devised here can be easily generalized to address other systems and devices where itinerant and correlation-localized degrees of freedom are intertwined on short lengthscales.

  6 citations

• A domain wall in twisted M-theory

  Jihwan Oh, Yehao Zhou

  SciPost Phys. 11, 077 (2021) · published 14 October 2021 | Toggle abstract · pdf

  We study a four-dimensional domain wall in twisted M-theory. The domain wall is engineered by intersecting D6 branes in the type IIA frame. We identify the classical algebra of operators on the domain wall in terms of a higher vertex operator algebra, which describes the holomorphic subsector of a 4d $\mathcal{N}=1$ supersymmetric field theory, and compute the associated mode algebra. We conjecture that the quantum deformation of the classical algebra is isomorphic to the bulk algebra of operators from which we establish twisted holography of the domain wall.

  6 citations

• Symmetries and topological operators, on average

  Andrea Antinucci, Giovanni Galati, Giovanni Rizi, Marco Serone

  SciPost Phys. 15, 125 (2023) · published 29 September 2023 | Toggle abstract · pdf

  We study Ward identities and selection rules for local correlators in disordered theories where a 0-form global symmetry of a QFT is explicitly broken by a random coupling $h$ but it re-emerges after quenched average. We consider $h$ space-dependent or constant. In both cases we construct the symmetry operator implementing the group action, topological after average. In the first case, relevant in statistical systems with random impurities, such symmetries can be coupled to external backgrounds and can be gauged, like ordinary symmetries in QFTs. We also determine exotic selection rules arising when symmetries emerge after average in the IR, explaining the origin of LogCFTs from symmetry considerations. In the second case, relevant in AdS/CFT to describe the dual boundary theory of certain bulk gravitational theories, the charge operator is not purely codimension-1, it can be defined only on homologically trivial cycles and on connected spaces. Selection rules for average correlators exist, yet such symmetries cannot be coupled to background gauge fields in ordinary ways and cannot be gauged. When the space is disconnected, in each connected component charge violation occurs, as expected from Euclidean wormholes in the bulk theory. Our findings show the obstruction to interpret symmetries emergent after average as gauged in the bulk.

  6 citations

• Triangular Gross-Pitaevskii breathers and Damski-Chandrasekhar shock waves

  M. Olshanii, D. Deshommes, J. Torrents, M. Gonchenko, V. Dunjko, G. E. Astrakharchik

  SciPost Phys. 10, 114 (2021) · published 26 May 2021 | Toggle abstract · pdf

  The recently proposed map [arXiv:2011.01415] between the hydrodynamic equations governing the two-dimensional triangular cold-bosonic breathers [Phys. Rev. X 9, 021035 (2019)] and the high-density zero-temperature triangular free-fermionic clouds, both trapped harmonically, perfectly explains the former phenomenon but leaves uninterpreted the nature of the initial ($t=0$) singularity. This singularity is a density discontinuity that leads, in the bosonic case, to an infinite force at the cloud edge. The map itself becomes invalid at times $t<0$. A similar singularity appears at $t = T/4$, where $T$ is the period of the harmonic trap, with the Fermi-Bose map becoming invalid at $t > T/4$. Here, we first map---using the scale invariance of the problem---the trapped motion to an untrapped one. Then we show that in the new representation, the solution [arXiv:2011.01415] becomes, along a ray in the direction normal to one of the three edges of the initial cloud, a freely propagating one-dimensional shock wave of a class proposed by Damski in [Phys.~Rev.~A 69, 043610 (2004)]. There, for a broad class of initial conditions, the one-dimensional hydrodynamic equations can be mapped to the inviscid Burgers' equation, which is equivalent to a nonlinear transport equation. More specifically, under the Damski map, the $t=0$ singularity of the original problem becomes, verbatim, the initial condition for the wave catastrophe solution found by Chandrasekhar in 1943 [Ballistic Research Laboratory Report No. 423 (1943)]. At $t=T/8$, our interpretation ceases to exist: at this instance, all three effectively one-dimensional shock waves emanating from each of the three sides of the initial triangle collide at the origin, and the 2D-1D correspondence between the solution of [arXiv:2011.01415] and the Damski-Chandrasekhar shock wave becomes invalid.

  6 citations

• Measurement-based quantum simulation of Abelian lattice gauge theories

  Hiroki Sukeno, Takuya Okuda

  SciPost Phys. 14, 129 (2023) · published 25 May 2023 | Toggle abstract · pdf

  Numerical simulation of lattice gauge theories is an indispensable tool in high energy physics, and their quantum simulation is expected to become a major application of quantum computers in the future. In this work, for an Abelian lattice gauge theory in $d$ spacetime dimensions, we define an entangled resource state (generalized cluster state) that reflects the spacetime structure of the gauge theory. We show that sequential single-qubit measurements with the bases adapted according to the former measurement outcomes induce a deterministic Hamiltonian quantum simulation of the gauge theory on the boundary. Our construction includes the $(2+1)$-dimensional Abelian lattice gauge theory simulated on three-dimensional cluster state as an example, and generalizes to the simulation of Wegner's lattice models $M_{(d,n)}$ that involve higher-form Abelian gauge fields. We demonstrate that the generalized cluster state has a symmetry-protected topological order with respect to generalized global symmetries that are related to the symmetries of the simulated gauge theories on the boundary.Our procedure can be generalized to the simulation of Kitaev's Majorana chain on a fermionic resource state. We also study the imaginary-time quantum simulation with two-qubit measurements and post-selections, and a classical-quantum correspondence, where the statistical partition function of the model $M_{(d,n)}$ is written as the overlap between the product of two-qubit measurement bases and the wave function of the generalized cluster state.

  6 citations

• Search for ultralight axion dark matter in a side-band analysis of a ${}^{199}$Hg free-spin precession signal

  C. Abel, N. J. Ayres, G. Ban, G. Bison, K. Bodek, V. Bondar, E. Chanel, C. B. Crawford, M. Daum, B. Dechenaux, S. Emmenegger, P. Flaux, W. C. Griffith, P. G. Harris, Y. Kermaidic, K. Kirch, S. Komposch, P. A. Koss, J. Krempel, B. Lauss, T. Lefort, Prajwal MohanMurthy, Oscar Naviliat Cuncic, D. Pais, F. M. Piegsa, Guillaume Pignol, M. Rawlik, D. Ries, Stephanie Roccia, D. Rozpedzik, Philipp Schmidt-Wellenburg, N. Severijns, Y. V. Stadnik, J. A. Thorne, A. Weis, E. Wursten, Jacek Zejma, Geza Zsigmond

  SciPost Phys. 15, 058 (2023) · published 9 August 2023 | Toggle abstract · pdf

  Ultra-low-mass axions are a viable dark matter candidate and may form a coherently oscillating classical field. Nuclear spins in experiments on Earth might couple to this oscillating axion dark-matter field, when propagating on Earth's trajectory through our Galaxy. This spin coupling resembles an oscillating pseudo-magnetic field which modulates the spin precession of nuclear spins. Here we report on the null result of a demonstration experiment searching for a frequency modulation of the free spin-precession signal of \magHg in a 1 $\mu$T magnetic field. Our search covers the axion mass range $10^{-16}$ eV $\lesssim m_a \lesssim 10^{-13}$ eV and achieves a peak sensitivity to the axion-nucleon coupling of $g_{aNN} \approx 3.5 \times 10^{-6}$ GeV$^{-1}$.

  6 citations

• Diagonal fields in critical loop models

  Sylvain Ribault

  SciPost Phys. Core 6, 020 (2023) · published 27 March 2023 | Toggle abstract · pdf

  In critical loop models, there exist diagonal fields with arbitrary conformal dimensions, whose $3$-point functions coincide with those of Liouville theory at $c\leq 1$. We study their $N$-point functions, which depend on the $2^{N-1}$ weights of topologically inequivalent loops on a sphere with $N$ punctures. Using a numerical conformal bootstrap approach, we find that $4$-point functions decompose into infinite but discrete linear combinations of conformal blocks. We conclude that diagonal fields belong to an extension of the $O(n)$ model.

  6 citations

• Determination of the rapidity evolution kernel from Drell-Yan data at low transverse momenta

  F. Hautmann, I. Scimemi, A. Vladimirov

  SciPost Phys. Proc. 8, 123 (2022) · published 13 July 2022 | Toggle abstract · pdf

  We report recent results on the extraction of the rapidity evolution kernel for Sudakov processes from experimental measurements of Drell-Yan (DY) transverse momentum distributions. We discuss the role of high-precision Large Hadron Collider (LHC) data, and illustrate the interplay of this analysis with transverse momentum dependent and collinear parton density functions.

  6 citations

• On exotic consistent anomalies in (1+1)$d$: A ghost story

  Chi-Ming Chang, Ying-Hsuan Lin

  SciPost Phys. 10, 119 (2021) · published 28 May 2021 | Toggle abstract · pdf

  We revisit 't Hooft anomalies in (1+1)$d$ non-spin quantum field theory, starting from the consistency and locality conditions, and find that consistent U(1) and gravitational anomalies cannot always be canceled by properly quantized (2+1)$d$ classical Chern-Simons actions. On the one hand, we prove that certain exotic anomalies can only be realized by non-reflection-positive or non-compact theories; on the other hand, without insisting on reflection-positivity, the exotic anomalies present a caveat to the inflow paradigm. For the mixed U(1) gravitational anomaly, we propose an inflow mechanism involving a mixed U(1)$\times$SO(2) classical Chern-Simons action with a boundary condition that matches the SO(2) gauge field with the (1+1)$d$ spin connection. Furthermore, we show that this mixed anomaly gives rise to an isotopy anomaly of U(1) topological defect lines. The isotopy anomaly can be canceled by an extrinsic curvature improvement term, but at the cost of creating a periodicity anomaly. We survey the holomorphic $bc$ ghost system which realizes all the exotic consistent anomalies, and end with comments on a subtlety regarding the anomalies of finite subgroups of U(1).

  6 citations

• Quantum Monte Carlo detection of SU(2) symmetry breaking in the participation entropies of line subsystems

  David J. Luitz, Nicolas Laflorencie

  SciPost Phys. 2, 011 (2017) · published 24 March 2017 | Toggle abstract · pdf

  Using quantum Monte Carlo simulations, we compute the participation (Shannon-R\'enyi) entropies for groundstate wave functions of Heisenberg antiferromagnets for one-dimensional (line) subsystems of length $L$ embedded in two-dimensional ($L\times L$) square lattices. We also study the line entropy at finite temperature, i.e. of the diagonal elements of the density matrix, for three-dimensional ($L\times L\times L$) cubic lattices. The breaking of SU(2) symmetry is clearly captured by a universal logarithmic scaling term $l_q\ln L$ in the R\'enyi entropies, in good agreement with the recent field-theory results of Misguish, Pasquier and Oshikawa [arXiv:1607.02465]. We also study the dependence of the log prefactor $l_q$ on the R\'enyi index $q$ for which a transition is detected at $q_c\simeq 1$.

  6 citations