TY - JOUR AU - Møller, Frederik AU - Nagy, Botond AU - Kormos, Márton AU - Takács, Gábor TI - Dynamical separation of charge and energy transport in one-dimensional Mott insulators JF - PHYSICAL REVIEW B J2 - PHYS REV B VL - 109 PY - 2024 IS - 16 SN - 2469-9950 DO - 10.1103/PhysRevB.109.L161112 UR - https://m2.mtmt.hu/api/publication/34818513 ID - 34818513 AB - One-dimensional Mott insulators can be described using the sine-Gordon model, an integrable quantum field theory that provides the low-energy effective description of several one-dimensional gapped condensed matter systems, including recent realizations with trapped ultracold atoms. Employing the theory of generalized hydrodynamics, we demonstrate that this model exhibits separation of the transport of topological charge vs energy. Analysis of the quasiparticle dynamics reveals that the mechanism behind the separation is the reflective scattering between topologically charged kinks/antikinks. The effect of these scattering events is most pronounced at strong coupling and low temperatures, where the distribution of quasiparticles is narrow compared to the reflective scattering amplitude. This effect results in a distinctively shaped “arrowhead” light cone for the topological charge. LA - English DB - MTMT ER - TY - JOUR AU - Szász-Schagrin, Dávid AU - Lovas, Lia Izabella AU - Takács, Gábor TI - Nonequilibrium time evolution in the sine-Gordon model JF - PHYSICAL REVIEW B J2 - PHYS REV B VL - 109 PY - 2024 IS - 1 SN - 2469-9950 DO - 10.1103/PhysRevB.109.014308 UR - https://m2.mtmt.hu/api/publication/34508958 ID - 34508958 N1 - Department of Theoretical Physics, Institute of Physics, Budapest University of Technology and Economics, Muegyetem rkp. 3, Budapest, H-1111, Hungary BME-MTA Momentum Statistical Field Theory Research Group, Institute of Physics, Budapest University of Technology and Economics, Muegyetem rkp. 3, Budapest, H-1111, Hungary Kavli Institute for Theoretical Physics, University of California, Santa Barbara, 93106, CA, United States HUN-REN-BME Quantum Dynamics and Correlations Research Group, Institute of Physics, Budapest University of Technology and Economics, Muegyetem rkp. 3, Budapest, H-1111, Hungary Export Date: 15 February 2024; Cited By: 0 LA - English DB - MTMT ER - TY - JOUR AU - Nagy, Botond AU - Kormos, Márton AU - Takács, Gábor TI - Thermodynamics and fractal Drude weights in the sine-Gordon model JF - PHYSICAL REVIEW B J2 - PHYS REV B VL - 108 PY - 2023 IS - 24 SN - 2469-9950 DO - 10.1103/PhysRevB.108.L241105 UR - https://m2.mtmt.hu/api/publication/34431639 ID - 34431639 N1 - Export Date: 21 December 2023; Cited By: 0 AB - The sine-Gordon model is a paradigmatic quantum field theory that provides the low-energy effective description of many gapped one-dimensional systems. Despite this fact, its complete thermodynamic description in all its regimes has been lacking. Here, we fill this gap and derive the framework that captures its thermodynamics and serves as the basis of its hydrodynamic description. As a first application, we compute the Drude weight characterizing the ballistic transport of topological charge and demonstrate that its dependence on the value of the coupling shows a fractal structure, similar to the gapless phase of the XXZ spin chain. The thermodynamic framework can be applied to study other features of nonequilibrium dynamics in the sine-Gordon model using generalized hydrodynamics, opening the way to a wide array of theoretical studies and potential novel experimental predictions. LA - English DB - MTMT ER - TY - JOUR AU - Martínez-Carracedo, Gabriel AU - Oroszlány, László AU - García-Fuente, Amador AU - Szunyogh, László AU - Ferrer, Jaime TI - Electrically driven singlet-triplet transition in triangulene spin-1 chains JF - PHYSICAL REVIEW B J2 - PHYS REV B VL - 107 PY - 2023 IS - 3 PG - 5 SN - 2469-9950 DO - 10.1103/PhysRevB.107.035432 UR - https://m2.mtmt.hu/api/publication/33644685 ID - 33644685 LA - English DB - MTMT ER - TY - JOUR AU - Szász-Schagrin, Dávid AU - Takács, Gábor TI - False vacuum decay in the ( 1 + 1 )-dimensional φ 4 theory JF - PHYSICAL REVIEW D J2 - PHYS REV D VL - 106 PY - 2022 IS - 2 SN - 2470-0010 DO - 10.1103/PhysRevD.106.025008 UR - https://m2.mtmt.hu/api/publication/32940001 ID - 32940001 N1 - Department of Theoretical Physics, Institute of Physics, Budapest University of Technology and Economics, Muegyetem rakpart 3, Budapest, H-1111, Hungary BME-MTA Momentum Statistical Field Theory Research Group, Institute of Physics, Budapest University of Technology and Economics, Muegyetem rakpart 3, Budapest, H-1111, Hungary MTA-BME Quantum Dynamics and Correlations Research Group (ELKH), Institute of Physics, Budapest University of Technology and Economics, Muegyetem rakpart 3, Budapest, H-1111, Hungary Export Date: 4 August 2022 AB - The false vacuum is a metastable state that can occur in quantum field theory, and its decay was first studied semiclassically by Coleman. In this work, we consider the 1+1 dimensional φ4 theory, which is the simplest model that provides a realization of this problem. We realize the decay as a quantum quench and study the subsequent evolution using a truncated Hamiltonian approach. In the thin wall limit, the decay rate can be described in terms of the mass of the kink interpolating between the vacua in the degenerate limit and the energy density difference between the false and true vacuum once the degeneracy is lifted by a symmetry breaking field, also known as the latent heat. We demonstrate that the numerical simulations agree well with the theoretical prediction for several values of the coupling in a range of the value of the latent heat, apart from a normalization factor, which only depends on the interaction strength. LA - English DB - MTMT ER - TY - JOUR AU - Horváth, Dávid AU - Hódsági, Kristóf AU - Takács, Gábor TI - Chirally factorised truncated conformal space approach JF - COMPUTER PHYSICS COMMUNICATIONS J2 - COMPUT PHYS COMMUN VL - 277 PY - 2022 PG - 24 SN - 0010-4655 DO - 10.1016/j.cpc.2022.108376 UR - https://m2.mtmt.hu/api/publication/32794934 ID - 32794934 N1 - SISSA, INFN Sezione di Trieste, Italy Department of Theoretical Physics, Budapest University of Technology and Economics, Műegyetem rkp. 3, Budapest, H-1111, Hungary BME-MTA Statistical Field Theory ‘Lendület’ Research Group, Budapest University of Technology and Economics, Hungary MTA-BME Quantum Correlations Group (ELKH), Budapest University of Technology and Economics, Hungary Export Date: 3 June 2022 CODEN: CPHCB Correspondence Address: Takács, G.; Department of Theoretical Physics, Műegyetem rkp. 3, Hungary; email: takacs.gabor@ttk.bme.hu AB - Truncated Conformal Space Approach (TCSA) is a highly efficient method to compute spectra, operator matrix elements and time evolution in quantum field theories defined as relevant perturbations of 1+1-dimensional conformal field theories. However, similarly to other exact diagonalisation methods, TCSA is ridden with the “curse of dimensionality”: the dimension of the Hilbert space increases exponentially with the (square root of the) truncation level, limiting its precision by the available memory resources. Here we describe an algorithm which exploits the chiral factorisation property of conformal field theory with periodic boundary conditions to achieve a substantial improvement in the truncation level. The Chirally Factorised TCSA (CFTCSA) algorithm presented here works with inputs describing the necessary CFT data in a specified format. It makes possible much more precise calculations with given computing resources and extends the reach of the method to problems requiring large Hilbert space dimensions. In fact, it has already been used in a number of recent works ranging from determination of form factors, through studying confinement of topological excitations to non-equilibrium dynamics. Besides the description of the algorithm, a MATLAB implementation of the algorithm is also provided as an ancillary file package, supplemented with example codes computing spectra, matrix elements and time evolution, and with CFT data for three different quantum field theories. We also give a detailed how-to guide for constructing the required CFT data for Virasoro minimal models with central charge c<1, and for the massless free boson with c=1. LA - English DB - MTMT ER - TY - JOUR AU - Szász-Schagrin, Dávid AU - Lovas, Lia Izabella AU - Takács, Gábor TI - Quantum quenches in an interacting field theory: Full quantum evolution versus semiclassical approximations JF - PHYSICAL REVIEW B J2 - PHYS REV B VL - 105 PY - 2022 IS - 1 SN - 2469-9950 DO - 10.1103/PhysRevB.105.014305 UR - https://m2.mtmt.hu/api/publication/32584991 ID - 32584991 N1 - BME Momentum Statistical Field Theory Research Group, Department of Theoretical Physics, Budapest University of Technology and Economics, Müegyetem rkp. 3, Budapest, H-1111, Hungary Department of Physics, Institute for Advanced Study, Technical University of Munich, Garching, D-85748, Germany Munich Center for Quantum Science and Technology (MQST), München, D-80799, Germany MTA-BME Quantum Correlations Group (ELKH), Department of Theoretical Physics, Budapest University of Technology and Economics, Müegyetem rkp. 3, Budapest, H-1111, Hungary Export Date: 7 March 2022 LA - English DB - MTMT ER - TY - CHAP AU - Kirchknopf, Péter AU - Almási, I. AU - Radócz, Gábor AU - Nemes, I. AU - Szalóki, Imre AU - Völgyesi, P. ED - Jószai, I TI - VVER-440 típusú kiégett üzemanyagkazetták nukleáris biztosítéki felügyeleti célú vizsgálata a hasadási termékek gamma-spektrometriai mérésével T2 - Őszi Radiokémiai Napok 2021 PB - Magyar Kémikusok Egyesülete (MKE) CY - Budapest SN - 9786156018076 PY - 2021 SP - 112 EP - 112 PG - 1 UR - https://m2.mtmt.hu/api/publication/33633681 ID - 33633681 LA - Hungarian DB - MTMT ER - TY - CHAP AU - Szarvas, Csongor Kristóf AU - Kirchknopf, Péter AU - István, Almási AU - Gergely, Dósa AU - Katalin, Zsuzsanna Szabó AU - Cong, Tam Nguyen AU - Péter, Völgyesi AU - Radócz, Gábor AU - Szalóki, Imre ED - Jószai, I TI - DESIGN AND OPTIMIZATION OF A LOW-BACKGROUND GAMMA SPECTROMETER FOR FORENSIC AND IN-SITU ANALYSIS T2 - Őszi Radiokémiai Napok 2021 PB - Magyar Kémikusok Egyesülete (MKE) CY - Budapest SN - 9786156018076 PY - 2021 SP - 111 EP - 111 PG - 1 UR - https://m2.mtmt.hu/api/publication/33633650 ID - 33633650 LA - Hungarian DB - MTMT ER - TY - CHAP AU - Szarvas, Csongor Kristóf AU - Kirchknopf, Péter AU - Almási, István AU - Dósa, Gergely AU - Szabó, Katalin Zsuzsanna AU - Nguyen, Cong Tam AU - Völgyesi, Péter AU - Radócz, Gábor AU - Szalóki, Imre ED - Jószai, I TI - Alacsony hátterű gamma-spektrometriai mérőrendszer tervezése és optimalizálása törvényszéki és in-situ analitikai célokra T2 - Őszi Radiokémiai Napok 2021 PB - Magyar Kémikusok Egyesülete (MKE) CY - Budapest SN - 9786156018076 PY - 2021 SP - 110 UR - https://m2.mtmt.hu/api/publication/33633630 ID - 33633630 LA - Hungarian DB - MTMT ER -