Publications

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• Branch Point Twist Field Form Factors in the sine-Gordon Model II: Composite Twist Fields and Symmetry Resolved Entanglement

  David X. Horvath, Pasquale Calabrese, Olalla A. Castro-Alvaredo

  SciPost Phys. 12, 088 (2022) · published 10 March 2022 | Toggle abstract · pdf

  In this paper we continue the programme initiated in Part I, that is the study of entanglement measures in the sine-Gordon model. In both parts, we have focussed on one specific technique, that is the well-known connection between branch point twist field correlators and measures of entanglement in 1+1D integrable quantum field theory. Our papers apply this technique for the first time to a non-diagonal theory with an involved particle spectrum, the sine-Gordon model. In this Part II we focus on a different entanglement measure, the symmetry resolved entanglement, and develop its associated twist field description, exploiting the underlying U(1) symmetry of the theory. In this context, conventional branch point twist fields are no longer the fields required, but instead we must work with one of their composite generalisations, which can be understood as the field resulting from the fusion of a standard branch point twist field and the sine-Gordon exponential field associated with U(1) symmetry. The resulting composite twist field has correlators which as usual admit a form factor expansion. In this paper we write the associated form factor equations and solve them for various examples in the breather sector by using the method of angular quantisation. We show that, in the attractive regime, this is the sector which provides the leading contribution to the symmetry resolved entropies, both Renyi and von Neumann. We compute the latter in the limit of a large region size and show that they satisfy the property of equipartition, that is the leading contribution to the symmetry resolved entanglement is independent of the symmetry sector.

  29 citations

• New sensitivity of current LHC measurements to vector-like quarks

  Andy Buckley, Jonathan M. Butterworth, Louie Corpe, Danping Huang, Puwen Sun

  SciPost Phys. 9, 069 (2020) · published 11 November 2020 | Toggle abstract · pdf

  Quark partners with non-chiral couplings appear in several extensions of the Standard Model. They may have non-trivial generational structure to their couplings, and may be produced either in pairs via the strong and EM interactions, or singly via the new couplings of the model. Their decays often produce heavy quarks and gauge bosons, which will contribute to a variety of already-measured "Standard Model" cross-sections at the LHC. We present a study of the sensitivity of such published LHC measurements to vector-like quarks, first comparing to limits already obtained from dedicated searches, and then broadening to some so-far unstudied parameter regions.

  29 citations

• Evaluation of time-dependent correlators after a local quench in iPEPS: hole motion in the t-J model

  Claudius Hubig, Annabelle Bohrdt, Michael Knap, Fabian Grusdt, J. Ignacio Cirac

  SciPost Phys. 8, 021 (2020) · published 6 February 2020 | Toggle abstract · pdf

  Infinite projected entangled pair states (iPEPS) provide a convenient variational description of infinite, translationally-invariant two-dimensional quantum states. However, the simulation of local excitations is not directly possible due to the translationally-invariant ansatz. Furthermore, as iPEPS are either identical or orthogonal, expectation values between different states as required during the evaluation of non-equal-time correlators are ill-defined. Here, we show that by introducing auxiliary states on each site, it becomes possible to simulate both local excitations and evaluate non-equal-time correlators in an iPEPS setting under real-time evolution. We showcase the method by simulating the t-J model after a single hole has been placed in the half-filled antiferromagnetic background and evaluating both return probabilities and spin correlation functions, as accessible in quantum gas microscopes.

  28 citations

• Electronic structure of the candidate 2D Dirac semimetal SrMnSb2: a combined experimental and theoretical study

  S. V. Ramankutty, J. Henke, A. Schiphorst, R. Nutakki, S. Bron, G. Araizi-Kanoutas, S. K. Mishra, Lei Li, Y. K. Huang, T. K. Kim, M. Hoesch, C. Schlueter, T. -L. Lee, A. de Visser, Zhicheng Zhong, Jasper van Wezel, E. van Heumen, M. S. Golden

  SciPost Phys. 4, 010 (2018) · published 21 February 2018 | Toggle abstract · pdf

  SrMnSb$_2$ is suggested to be a magnetic topological semimetal. It contains square, 2D Sb planes with non-symmorphic crystal symmetries that could protect band crossings, offering the possibility of a quasi-2D, robust Dirac semi-metal in the form of a stable, bulk (3D) crystal. Here, we report a combined and comprehensive experimental and theoretical investigation of the electronic structure of SrMnSb$_2$, including the first ARPES data on this compound. SrMnSb$_2$ possesses a small Fermi surface originating from highly 2D, sharp and linearly dispersing bands (the Y-states) around the (0,$\pi$/a)-point in $k$-space. The ARPES Fermi surface agrees perfectly with that from bulk-sensitive Shubnikov de Haas data from the same crystals, proving the Y$-$states to be responsible for electrical conductivity in SrMnSb$_2$. DFT and tight binding (TB) methods are used to model the electronic states, and both show good agreement with the ARPES data. Despite the great promise of the latter, both theory approaches show the Y-states to be gapped above E$_F$, suggesting trivial topology. Subsequent analysis within both theory approaches shows the Berry phase to be zero, indicating the non-topological character of the transport in SrMnSb$_2$, a conclusion backed up by the analysis of the quantum oscillation data from our crystals.

  28 citations

• Gauging permutation symmetries as a route to non-Abelian fractons

  Abhinav Prem, Dominic J. Williamson

  SciPost Phys. 7, 068 (2019) · published 28 November 2019 | Toggle abstract · pdf

  We discuss the procedure for gauging on-site $\mathbb{Z}_2$ global symmetries of three-dimensional lattice Hamiltonians that permute quasi-particles and provide general arguments demonstrating the non-Abelian character of the resultant gauged theories. We then apply this general procedure to lattice models of several well known fracton phases: two copies of the X-Cube model, two copies of Haah's cubic code, and the checkerboard model. Where the former two models possess an on-site $\mathbb{Z}_2$ layer exchange symmetry, that of the latter is generated by the Hadamard gate. For each of these models, upon gauging, we find non-Abelian subdimensional excitations, including non-Abelian fractons, as well as non-Abelian looplike excitations and Abelian fully mobile pointlike excitations. By showing that the looplike excitations braid non-trivially with the subdimensional excitations, we thus discover a novel gapped quantum order in 3D, which we term a "panoptic" fracton order. This points to the existence of parent states in 3D from which both topological quantum field theories and fracton states may descend via quasi-particle condensation. The gauged cubic code model represents the first example of a gapped 3D phase supporting (inextricably) non-Abelian fractons that are created at the corners of fractal operators.

  28 citations

• EXCESS workshop: Descriptions of rising low-energy spectra

  P. Adari, A. Aguilar-Arevalo, D. Amidei, G. Angloher, E. Armengaud, C. Augier, L. Balogh, S. Banik, D. Baxter, C. Beaufort, G. Beaulieu, V. Belov, Y. Ben Gal, G. Benato, A. Benoît, A. Bento, L. Bergé, A. Bertolini, R. Bhattacharyya, J. Billard, I.M. Bloch, A. Botti, R. Breier, G. Bres, J-.L. Bret, A. Broniatowski, A. Brossard, C. Bucci, R. Bunker, M. Cababie, M. Calvo, P. Camus, G. Cancelo, L. Canonica, F. Cappella, L. Cardani, J.-F. Caron, N. Casali, G.del Castello, A. Cazes, R. Cerulli, B.A. Cervantes Vergara, D. Chaize, M. Chapellier, L. Chaplinsky, F. Charlieux, M. Chaudhuri, A.E. Chavarria, G. Chemin, R. Chen, H. Chen, F. Chierchie, I. Colantoni, J. Colas, J. Cooley, J.-M. Coquillat, E.C. Corcoran, S. Crawford, M. Crisler, A. Cruciani, P. Cushman, A. D'Addabbo, J.C. D'Olivo, A. Dastgheibi-Fard, M. De Jésus, Y. Deng, J.B. Dent, E.L. Depaoli, K. Dering, S. Dharani, S. Di Lorenzo, A. Drlica-Wagner, L. Dumoulin, D. Durnford, B. Dutta, L. Einfalt, A. Erb, A. Erhart, R. Essig, J. Estrada, E. Etzion, O. Exshaw, F. Favela-Perez, F. v. Feilitzsch, G. Fernandez Moroni, N. Ferreiro Iachellini, S. Ferriol, S. Fichtinger, E. Figueroa-Feliciano, J.-B. Filippini, D. Filosofov, J. A. Formaggio, M. Friedl, S. Fuard, D. Fuchs, A. Fuss, R. Gaïor, A. Garai, C. Garrah, J. Gascon , G. Gerbier, M. Ghaith, V.M. Ghete, D. Gift, I. Giomataris, G. Giroux, A. Giuliani, P. Gorel, P. Gorla, C. Goupy, J. Goupy, C. Goy, M. Gros, P. Gros, Y. Guardincerri, C. Guerin, V. Guidi, O. Guillaudin, S. Gupta, E. Guy, P. Harrington, D. Hauff, S. T. Heine, S. A. Hertel, S.E. Holland, Z. Hong, E.W. Hoppe, T.W. Hossbach, J.-C. Ianigro, V. Iyer, A. Jastram, M. Ješkovský, Y. Jin, J. Jochum, J. P. Johnston, A. Juillard, D. Karaivanov, V. Kashyap, I. Katsioulas, S. Kazarcev, M. Kaznacheeva, F. Kelly, B. Kilminster, A. Kinast, L. Klinkenberg, H. Kluck, P. Knights, Y. Korn, H. Kraus, B. von Krosigk, A. Kubik, N.A. Kurinsky, J. Lamblin, A. Langenkämper, S. Langrock, T. Lasserre, H. Lattaud, P. Lautridou, I. Lawson, S.J. Lee, M. Lee, A. Letessier-Selvon, D. Lhuillier, M. Li, Y.-T. Lin, A. Lubashevskiy, R. Mahapatra, S. Maludze, M. Mancuso, I. Manthos, L. Marini, S. Marnieros, R.D. Martin, A. Matalon, J. Matthews, B. Mauri, D. W. Mayer, A. Mazzolari, E. Mazzucato, H. Meyer zu Theenhausen, E. Michielin, J. Minet, N. Mirabolfathi, K. v. Mirbach, D. Misiak, P. Mitra, J-.L. Mocellin, B. Mohanty, V. Mokina, J.-P. Mols, A. Monfardini, F. Mounier, S. Munagavalasa, J.-F. Muraz, X.-F. Navick, T. Neep, H. Neog, H. Neyrial, K. Nikolopoulos, A. Nilima, C. Nones, V. Novati, P. O'Brien, L. Oberauer, E. Olivieri, M. Olmi, A. Onillon, C. Oriol, A. Orly, J.L. Orrell, T. Ortmann, C.T. Overman, C. Pagliarone, V. Palušová, P. Pari, P. K. Patel, L. Pattavina, F. Petricca, A. Piers, H. D. Pinckney, M.-C. Piro, M. Platt, D. Poda, D. Ponomarev, W. Potzel, P. Povinec, F. Pröbst, P. Privitera, F. Pucci, K. Ramanathan, J.-S. Real, T. Redon, F. Reindl, R. Ren, A. Robert, J.Da Rocha, D. Rodrigues, R. Rogly, J. Rothe, N. Rowe, S. Rozov, I. Rozova, T. Saab, N. Saffold, T. Salagnac, J. Sander, V. Sanglard, D. Santos, Y. Sarkis, V. Savu, G. Savvidis, I. Savvidis, S. Schönert, K. Schäffner, N. Schermer, J. Schieck, B. Schmidt, D. Schmiedmayer, C. Schwertner, L. Scola, M. Settimo, Ye. Shevchik, V. Sibille, I. Sidelnik, A. Singal, R. Smida, M. Sofo Haro, T. Soldner, J. Stachurska, M. Stahlberg, L. Stefanazzi, L. Stodolsky, C. Strandhagen, R. Strauss, A. Stutz, R. Thomas, A. Thompson, J. Tiffenberg, C. Tomei, M. Traina, S. Uemura, I. Usherov, L. Vagneron, W. Van De Pontseele, F.A. Vazquez de Sola Fernandez, M. Vidal, M. Vignati, A.L. Virto, M. Vivier, T. Volansky, V. Wagner, F. Wagner, J. Walker, R. Ward, S.L. Watkins, A. Wex, M. Willers, M.J. Wilson, L. Winslow, E. Yakushev, T.-T. Yu, M. Zampaolo, A. Zaytsev, V. Zema, D. Zinatulina, A. Zolotarova

  SciPost Phys. Proc. 9, 001 (2022) · published 9 August 2022 | Toggle abstract · pdf

  Many low-threshold experiments observe sharply rising event rates of yet unknown origins below a few hundred eV, and larger than expected from known backgrounds. Due to the significant impact of this excess on the dark matter or neutrino sensitivity of these experiments, a collective effort has been started to share the knowledge about the individual observations. For this, the EXCESS Workshop was initiated. In its first iteration in June 2021, ten rare event search collaborations contributed to this initiative via talks and discussions. The contributing collaborations were CONNIE, CRESST, DAMIC, EDELWEISS, MINER, NEWS-G, NUCLEUS, RICOCHET, SENSEI and SuperCDMS. They presented data about their observed energy spectra and known backgrounds together with details about the respective measurements. In this paper, we summarize the presented information and give a comprehensive overview of the similarities and differences between the distinct measurements. The provided data is furthermore publicly available on the workshop’s data repository together with a plotting tool for visualization.

  28 citations

• Applications of dispersive sum rules: $ε$-expansion and holography

  Dean Carmi, Joao Penedones, Joao A. Silva, Alexander Zhiboedov

  SciPost Phys. 10, 145 (2021) · published 14 June 2021 | Toggle abstract · pdf

  We use Mellin space dispersion relations together with Polyakov conditions to derive a family of sum rules for Conformal Field Theories (CFTs). The defining property of these sum rules is suppression of the contribution of the double twist operators. Firstly, we apply these sum rules to the Wilson-Fisher model in $d=4-\epsilon$ dimensions. We re-derive many of the known results to order $\epsilon^4$ and we make new predictions. No assumption of analyticity down to spin $0$ was made. Secondly, we study holographic CFTs. We use dispersive sum rules to obtain tree-level and one-loop anomalous dimensions. Finally, we briefly discuss the contribution of heavy operators to the sum rules in UV complete holographic theories.

  28 citations

• Free fermions at the edge of interacting systems

  Jean-Marie Stéphan

  SciPost Phys. 6, 057 (2019) · published 10 May 2019 | Toggle abstract · pdf

  We study the edge behavior of inhomogeneous one-dimensional quantum systems, such as Lieb-Liniger models in traps or spin chains in spatially varying magnetic fields. For free systems these fall into several universality classes, the most generic one being governed by the Tracy-Widom distribution. We investigate in this paper the effect of interactions. Using semiclassical arguments, we show that since the density vanishes to leading order, the strong interactions in the bulk are renormalized to zero at the edge, which simply explains the survival of Tracy-Widom scaling in general. For integrable systems, it is possible to push this argument further, and determine exactly the remaining length scale which controls the variance of the edge distribution. This analytical prediction is checked numerically, with excellent agreement. We also study numerically the edge scaling at fronts generated by quantum quenches, which provide new universality classes awaiting theoretical explanation.

  28 citations

• EFT and the SUSY index on the 2nd sheet

  Davide Cassani, Zohar Komargodski

  SciPost Phys. 11, 004 (2021) · published 9 July 2021 | Toggle abstract · pdf

  The counting of BPS states in four-dimensional ${\cal N}=1$ theories has attracted a lot of attention in recent years. For superconformal theories, these states are in one-to-one correspondence with local operators in various short representations. The generating function for this counting problem has branch cuts and hence several Cardy-like limits, which are analogous to high-temperature limits. Particularly interesting is the second sheet, which has been shown to capture the microstates and phases of supersymmetric black holes in AdS$_5$. Here we present a 3d Effective Field Theory (EFT) approach to the high-temperature limit on the second sheet. We use the EFT to derive the behavior of the index at orders $\beta^{-2},\beta^{-1},\beta^0$. We also make a conjecture for $O(\beta)$, where we argue that the expansion truncates up to exponentially small corrections. An important point is the existence of vector multiplet zero modes, unaccompanied by massless matter fields. The runaway of Affleck-Harvey-Witten is however avoided by a non-perturbative confinement mechanism. This confinement mechanism guarantees that our results are robust.

  28 citations

• Quantum Bose-Fermi droplets

  Debraj Rakshit, Tomasz Karpiuk, Mirosław Brewczyk, Mariusz Gajda

  SciPost Phys. 6, 079 (2019) · published 28 June 2019 | Toggle abstract · pdf

  We study the stability of a zero temperature mixture of attractively interacting degenerate bosons and spin-polarized fermions in the absence of confinement. We demonstrate that higher order corrections to the standard mean-field energy can lead to a formation of Bose-Fermi liquid droplets -- self-bound systems in three-dimensional space. The stability analysis of the homogeneous case is supported by numerical simulations of finite systems by explicit inclusion of surface effects. We discuss the experimental feasibility of formation of quantum droplets and indicate the main obstacle -- inelastic three-body collisions.

  28 citations