Publications

Order by: publication date number of citations

• Properties of non-relativistic string theory

  E.A. Bergshoeff, J. Lahnsteiner, L. Romano, C. Simsek

  SciPost Phys. Proc. 4, 001 (2021) · published 13 August 2021 | Toggle abstract · pdf

  We show how Newton-Cartan geometry can be generalized to String Newton-Cartan geometry which is the geometry underlying non-relativistic string theory. Several salient properties of non-relativistic string theory in this geometric background are presented and a discussion of possible research for the future is outlined.

• Some recent results on renormalization-group properties of quantum field theories

  Robert Shrock

  SciPost Phys. Proc. 6, 005 (2022) · published 31 May 2022 | Toggle abstract · pdf

  We discuss some higher-loop studies of renormalization-group flows and fixed points in various quantum field theories.

• Lattice simulations of the QCD chiral transition at real $\mu_B$

  Attila Pasztor, Szabolcs Borsanyi, Zoltan Fodor, Matteo Giordano, Sandor D. Katz, Daniel Nogradi, Chik Him Wong

  SciPost Phys. Proc. 6, 002 (2022) · published 31 May 2022 | Toggle abstract · pdf

  Most lattice studies of hot and dense QCD matter rely on extrapolation from zero or imaginary chemical potentials. The ill-posedness of numerical analytic continuation puts severe limitations on the reliability of such methods. We studied the QCD chiral transition at finite real baryon density with the more direct sign reweighting approach. We simulate up to a baryochemical potential-temperature ratio of $\mu_B/T=2.7$, covering the RHIC Beam Energy Scan range, and penetrating the region where methods based on analytic continuation are unpredictive. This opens up a new window to study QCD matter at finite $\mu_B$ from first principles.

• A sharp transition in quantum chaos and thermodynamics of mass deformed SYK model

  Tomoki Nosaka

  SciPost Phys. Proc. 4, 006 (2021) · published 13 August 2021 | Toggle abstract · pdf

  We review our recent work [arXiv:2009.10759] where we studied the chaotic property of the two coupled Sachdev-Ye-Kitaev systems exhibiting a Hawking-Page like phase transition. By computing the out-of-time-ordered correlator in the large N limit by using the bilocal field formalism, we found that the chaos exponent of this model shows a discontinuous fall-off at the phase transition temperature. Hence in this model the Hawking-Page like transition is correlated with a transition in chaoticity, as expected from the relation between a black hole geometry and the chaotic behavior in the dual field theory.

• Mechanical work extraction from an error-prone active dynamic Szilard engine

  Luca Cocconi, Paolo Malgaretti, Holger Stark

  SciPost Phys. 19, 138 (2025) · published 25 November 2025 | Toggle abstract · pdf

  Isothermal information engines operate by extracting net work from a single heat bath through measurement and feedback control. In this work, we analyze a {realistic} active Szilard engine operating on a single self-propelled particle by means of steric interaction with an externally controlled mechanical element. In particular, we provide a comprehensive study of how finite measurement accuracy affects the engine's work and power output, as well as the cost of operation. Having established the existence of non-trivial optima for work and power output, we study the dependence of their loci on the measurement error parameters and identify conditions for their positivity under one-shot and cyclic engine operation. We also demonstrate that a suitably defined efficiency of information-to-work conversion, which at equilibrium is bounded above by unity as a consequence of Landauer's principle, may here be made arbitrarily large by increasing the active Péclet number of the particle. Equivalently, for such a nonequilibrium efficiency to remain bounded above by unity, the athermal motion of the bath particles needs to be accounted for explicitly. Notably, the information efficiency for one-shot operation exhibits a discontinuous transition and a non-monotonic dependence on the measurement precision. Finally, we show that cyclic operation improves information efficiency by harvesting residual mutual information between successive measurements.

• On non-canonical degrees of freedom

  Eoin Quinn

  SciPost Phys. 10, 075 (2021) · published 25 March 2021 | Toggle abstract · pdf

  Non-canonical degrees of freedom provide one of the most promising routes towards characterising a range of important phenomena in condensed matter physics. Potential candidates include the pseudogap regime of the cuprates, heavy-fermion behaviour, and also indeed magnetically ordered systems. Nevertheless it remains an open question whether non-canonical algebras can in fact provide legitimate quantum degrees of freedom. In this paper we survey progress made on this topic, complementing distinct approaches so as to obtain a unified description. In particular we obtain a novel exact representation for a self-energy-like object for non-canonical degrees of freedom. We further make a resummation of density correlations to obtain analogues of the RPA and GW approximations commonly employed for canonical degrees of freedom. We discuss difficulties related to generating higher-order approximations which are consistent with conservation laws, which represents an outstanding issue. We also discuss how the interplay between canonical and non-canonical degrees of freedom offers a useful paradigm for organising the phase diagram of correlated electronic behaviour.

• Exploring three-nucleon forces via three- and four-nucleon scattering

  Kimiko Sekiguchi

  SciPost Phys. Proc. 3, 029 (2020) · published 26 February 2020 | Toggle abstract · pdf

  Three-nucleon force effects in three- and four-nucleon scattering are discussed from an experimental point of view.

• Beyond Cooperation: The Role of Origin Countries in Deportation Efforts, Evidence from Mexico (1942 to 1964)

  Guadalupe Chavez

  Mig. Pol. 4, 005 (2025) · published 28 November 2025 | Toggle abstract · pdf

  For deportations to be carried out, host countries must secure inter-state cooperation with origin countries where they seek to deport noncitizens. However, origin countries may decide to cooperate or resist cooperation. This paper pushes the scholarship by exploring why some origin countries not only decide to cooperate but also become proactive actors in deportation efforts by encouraging and promoting the deportation of their citizens despite the economic and political costs. This paper unpacks this puzzle by analyzing why the Mexican government became a proactive actor in facilitating the deportation of its citizens from the 1940s to the 1960s. Drawing on state archival research in the U.S. and Mexico, I argue that the Mexican government became a proactive actor as a strategy to address its domestic challenges and to cultivate its diplomatic relations with the U.S. government and the benefits that came with such relation including the continuation of the Bracero Program, the largest guest worker program. This study makes two contributions. Empirically, this article provides an in-depth analysis on how Mexico, the country with the highest deportation flows in the Western Hemisphere, managed deportations during one of the largest U.S. removal operations. Second, by introducing the concept of proactiveness, it expands the field of migration diplomacy by unpacking the conditions that motivate origin countries to become proactive actors in deportation proceedings.

• Gluon saturation in proton and its contribution to single inclusive soft gluon production in high energy proton-nucleus collisions

  Ming Li

  SciPost Phys. Proc. 8, 162 (2022) · published 14 July 2022 | Toggle abstract · pdf

  The leading order single inclusive soft gluon production in high energy proton-nucleus (pA) collisions has been studied by various approaches for more than two decades. The first correction due to the gluon saturation in proton was analytically attempted recently through a diagrammatic approach in which only partial results were obtained. An important feature of the first saturation correction is that it includes both initial state and final state interactions. In this paper, we present the complete result derived from the Color Glass Condensate framework. Our approach is to analytically solve the classical Yang-Mills equations in the dilute-dense regime and then use the Lehmann-Symanzik-Zimmermann (LSZ) reduction formula to obtain gluon production from classical gluon fields.

• Josephson current through the SYK model

  Luca Dell'Anna

  SciPost Phys. 17, 120 (2024) · published 24 October 2024 | Toggle abstract · pdf

  We calculate the equilibrium Josephson current through a disordered interacting quantum dot described by a Sachdev-Ye-Kitaev model fully contacted by two BCS superconductors, such that all modes of the dot contribute to the coupling, which encodes hopping and spin-flip processes. We show that, at zero temperature and at the conformal limit, i.e. in the strong interacting limit, the Josephson current is suppressed by $U$, the strength of the interaction, as ln(U)/U and becomes universal, namely it gets independent on the superconducting gap. At finite temperature, instead, it depends on the ratio between the gap and the temperature. A proximity effect exists but the self-energy corrections induced by the coupling with the superconducting leads seem subleading as compared to the interaction self-energy and the tunneling matrix for large number of particles. Finally we compare the results of the original four-fermion model with those obtained considering zero interaction, two-fermions and a generalized $q$-fermion model.