Change search
Link to record
Permanent link

Direct link
BETA
Publications (4 of 4) Show all publications
Langmann, E. & Moosavi, P. (2019). Diffusive Heat Waves in Random Conformal Field Theory. Physical Review Letters, 122(2), Article ID 020201.
Open this publication in new window or tab >>Diffusive Heat Waves in Random Conformal Field Theory
2019 (English)In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 122, no 2, article id 020201Article in journal (Refereed) Published
Abstract [en]

We propose and study a conformal field theory (CFT) model with random position-dependent velocity that, as we argue, naturally emerges as an effective description of heat transport in one-dimensional quantum many-body systems with certain static random impurities. We present exact analytical results that elucidate how purely ballistic heat waves in standard CFT can acquire normal and anomalous diffusive contributions due to our impurities. Our results include impurity-averaged Green's functions describing the time evolution of the energy density and the heat current, and an explicit formula for the thermal conductivity that, in addition to a universal Drude peak, has a nontrivial real regular contribution that depends on details of the impurities.

Place, publisher, year, edition, pages
AMER PHYSICAL SOC, 2019
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:kth:diva-243955 (URN)10.1103/PhysRevLett.122.020201 (DOI)000456041800001 ()30720322 (PubMedID)2-s2.0-85060652301 (Scopus ID)
Funder
Swedish Research Council, 2016-05167
Note

QC 20190304

Available from: 2019-03-04 Created: 2019-03-04 Last updated: 2019-06-26Bibliographically approved
Langmann, E. & Moosavi, P. (2018). Finite-Time Universality in Nonequilibrium CFT. Journal of statistical physics, 172(2), 353-378
Open this publication in new window or tab >>Finite-Time Universality in Nonequilibrium CFT
2018 (English)In: Journal of statistical physics, ISSN 0022-4715, E-ISSN 1572-9613, Vol. 172, no 2, p. 353-378Article in journal (Refereed) Published
Abstract [en]

Recently, remarkably simple exact results were presented about the dynamics of heat transport in the local Luttinger model for nonequilibrium initial states defined by position-dependent temperature profiles. We present mathematical details on how these results were obtained. We also give an alternative derivation using only algebraic relations involving the energy-momentum tensor which hold true in any unitary conformal field theory (CFT). This establishes a simple universal correspondence between initial temperature profiles and the resulting heat-wave propagation in CFT. We extend these results to larger classes of nonequilibrium states. It is proposed that such universal CFT relations provide benchmarks to identify nonuniversal properties of nonequilibrium dynamics in other models.

Place, publisher, year, edition, pages
Springer, 2018
Keywords
Nonequilibrium dynamics, Conformal field theory, Heat and charge transport, Luttinger model
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:kth:diva-232397 (URN)10.1007/s10955-018-2025-x (DOI)000437829200004 ()2-s2.0-85044457468 (Scopus ID)
Funder
Swedish Research Council, 2016-05167
Note

QC 20180726

Available from: 2018-07-26 Created: 2018-07-26 Last updated: 2019-05-20Bibliographically approved
Langmann, E., Lebowitz, J. L., Mastropietro, V. & Moosavi, P. (2017). Time evolution of the Luttinger model with nonuniform temperature profile. Physical Review B, 95(23), Article ID 235142.
Open this publication in new window or tab >>Time evolution of the Luttinger model with nonuniform temperature profile
2017 (English)In: Physical Review B, ISSN 2469-9950, E-ISSN 2469-9969, Vol. 95, no 23, article id 235142Article in journal (Refereed) Published
Abstract [en]

We study the time evolution of a one-dimensional interacting fermion system described by the Luttinger model starting from a nonequilibrium state defined by a smooth temperature profile T (x). As a specific example we consider the case when T (x) is equal to T-L (T-R) far to the left (right). Using a series expansion in epsilon = 2(T-R -T-L)/(T-L + T-R), we compute the energy density, the heat current density, and the fermion two-point correlation function for all times t >= 0. For local (delta-function) interactions, the first two are computed to all orders, giving simple exact expressions involving the Schwarzian derivative of the integral of T (x). For nonlocal interactions, breaking scale invariance, we compute the nonequilibrium steady state (NESS) to all orders and the evolution to first order in epsilon. The heat current in the NESS is universal even when conformal invariance is broken by the interactions, and its dependence on T-L,T-R agrees with numerical results for the XXZ spin chain. Moreover, our analytical formulas predict peaks at short times in the transition region between different temperatures and show dispersion effects that, even if nonuniversal, are qualitatively similar to ones observed in numerical simulations for related models, such as spin chains and interacting lattice fermions.

Place, publisher, year, edition, pages
American Physical Society, 2017
National Category
Physical Sciences
Identifiers
urn:nbn:se:kth:diva-211012 (URN)10.1103/PhysRevB.95.235142 (DOI)000404018700002 ()2-s2.0-85024365790 (Scopus ID)
Funder
Swedish Research Council, 2016-05167
Note

QC 20170712

Available from: 2017-07-12 Created: 2017-07-12 Last updated: 2018-11-20Bibliographically approved
Langmann, E. & Moosavi, P. (2015). Construction by bosonization of a fermion-phonon model. Journal of Mathematical Physics, 56(9), Article ID 091902.
Open this publication in new window or tab >>Construction by bosonization of a fermion-phonon model
2015 (English)In: Journal of Mathematical Physics, ISSN 0022-2488, E-ISSN 1089-7658, Vol. 56, no 9, article id 091902Article in journal (Refereed) Published
Abstract [en]

We discuss an extension of the (massless) Thirring model describing interacting fermions in one dimension which are coupled to phonons and where all interactions are local. This fermion-phonon model can be solved exactly by bosonization.We present a construction and solution of this model which is mathematically rigorous by treating it as a continuum limit of a Luttinger-phonon model. A self-contained account of the mathematical results underlying bosonization is included, together with complete proofs.

National Category
Physical Sciences
Identifiers
urn:nbn:se:kth:diva-175654 (URN)10.1063/1.4930299 (DOI)000362569200020 ()2-s2.0-84941912006 (Scopus ID)
Note

QC 20151023

Available from: 2015-10-23 Created: 2015-10-19 Last updated: 2018-11-20Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0003-0011-2937

Search in DiVA

Show all publications