Publications

Order by: publication date number of citations

• Quantum-inspired tempering for ground state approximation using artificial neural networks

  Tameem Albash, Conor Smith, Quinn Campbell, Andrew D. Baczewski

  SciPost Phys. 14, 121 (2023) · published 19 May 2023 | Toggle abstract · pdf

  A large body of work has demonstrated that parameterized artificial neural networks (ANNs) can efficiently describe ground states of numerous interesting quantum many-body Hamiltonians. However, the standard variational algorithms used to update or train the ANN parameters can get trapped in local minima, especially for frustrated systems and even if the representation is sufficiently expressive. We propose a parallel tempering method that facilitates escape from such local minima. This methods involves training multiple ANNs independently, with each simulation governed by a Hamiltonian with a different "driver" strength, in analogy to quantum parallel tempering, and it incorporates an update step into the training that allows for the exchange of neighboring ANN configurations. We study instances from two classes of Hamiltonians to demonstrate the utility of our approach using Restricted Boltzmann Machines as our parameterized ANN. The first instance is based on a permutation-invariant Hamiltonian whose landscape stymies the standard training algorithm by drawing it increasingly to a false local minimum. The second instance is four hydrogen atoms arranged in a rectangle, which is an instance of the second quantized electronic structure Hamiltonian discretized using Gaussian basis functions. We study this problem in a minimal basis set, which exhibits false minima that can trap the standard variational algorithm despite the problem's small size. We show that augmenting the training with quantum parallel tempering becomes useful to finding good approximations to the ground states of these problem instances.

  1 citation

• Punitive Subjectivities and Emotions in Immigration Detention

  Alethia Fernández de la Reguera Ahedo

  Mig. Pol. 3, 004 (2024) · published 11 October 2024 | Toggle abstract · pdf

  In immigration detention centres, emotions run high; tensions, conflicts, anxiety, and affection occur amid bureaucratic procedures, paperwork, files, lists of people, systematisation of cases, buses that come and go with detainees, and people who will be deported. Although immigration detention belongs to administrative law, in practice, detention centres operate closer to penal detention. Little is known about the operation of these places in Mexico, including how punishment takes place in daily practice. Even less is known about the people who work there, especially the rationale and emotions behind their daily decisions and the different ways in which they collaborate with a system that promotes punishment as a central element of immigration detention. In this article, I study how fear and disgust are emotions embedded in institutional practices that reinforce punishment in immigration detention, while empathy can challenge it. I analyse working conditions and daily interactions in detention centres, immigration control facilities and their surroundings. I argue that immigration agents can develop punitive subjectivities to channel emotions derived from anxieties and frustrations of daily work, as well as to embrace a sense of institutional belonging and the illusion of order and control. However, border officers also show empathy towards migrants to cope with emotional distress and humanise their daily work. I intend to answer the questions in this paper: Under what institutional conditions do emotions become power in immigration detention settings? What do emotions reveal about the functioning of punishment in immigration detention centres? How do emotions expressed by INM agents (such as fear, disgust and empathy) enhance or challenge punitive subjectivities?

  1 citation

• (Inter)racialisation: the regulation of domestic and urban space in housing North-African migrants in 1960s and 1970s France

  Rébecca Suzanne Franco

  Mig. Pol. 1, 003 (2022) · published 25 May 2022 | Toggle abstract · pdf

  Literature on immigrant housing and assimilation has shown how housing policies perpetuate, create and contest racial boundaries. This paper argues for the necessity to look at the regulation of domestic space together with the regulation of the urban space. By reading “along” and “against” the archival grain, this paper looks at housing policies that targeted the North-African migrant population in the 1960s and 1970s in France as colonial continuities. French authorities ostensibly encouraged gendered assimilation through spatial politics and interventions in the domestic space. Literature on the French context has shown how this perpetuated racialisation in the housing process. Building upon feminist scholarship on gender, intimacy, and colonialism, this paper shows how these policies did not acknowledge interracialised households and prevented interracialised intimacies. This helps understand how housing policies can reinforce racialised exclusion by regulating racial boundaries in the urban space and the domestic space together.

  1 citation

• The ALPACA experiment: The project of the first sub-PeV gamma-ray observation in the southern sky

  Teruyoshi Kawashima for the ALPACA Collaboration

  SciPost Phys. Proc. 13, 008 (2023) · published 28 September 2023 | Toggle abstract · pdf

  The ALPACA experiment is a project aiming to observe sub-PeV gamma rays for the first time in the southern hemisphere. The main goal of ALPACA is to identify PeVatrons, the accelerators of Galactic PeV cosmic rays, by observing sub-PeV pion-decay gamma rays generated in interactions between PeV cosmic rays and the interstellar medium. This new air shower experiment is located at an altitude of 4,740 m above sea level in the middle of Mt. Chacaltaya in Bolivia. The air shower array consists of 401 scintillation counters covering an 83,000 m$^2$ surface area. In addition, a water-Cherenkov-type muon detector array with an area of 3,700 m$^2$ is installed to discriminate gamma rays from background cosmic rays. The prototype array ALPAQUITA will start data taking in 2022 and will extend to ALPACA in 2024. We report on a general introduction to ALPACA, the progress of the project, and the sensitivity to sub-PeV gamma rays.

  1 citation

• The Tunka-Grande scintillation array: Current results

  A. L. Ivanova, I. Astapov, P. Bezyazeekov, E. Bonvech, A. Borodin, N. Budnev, A. Bulan, D. Chernov, A. Chiavassa, A. Dyachok, A. Gafarov, A. Garmash, V. Grebenyuk, E. Gress, O. Gress, T. Gress, A. Grinyuk, O. Grishin, A. D. Ivanova, N. Kalmykov, V. Kindin, S. Kiryuhin, R. Kokoulin, K. Kompaniets, E. Korosteleva, V. Kozhin, E. Kravchenko, A. Kryukov, L. Kuzmichev, A. Lagutin, M. Lavrova, Y. Lemeshev, B. Lubsandorzhiev, N. Lubsandorzhiev, A. Lukanov, D. Lukyantsev, S. Malakhov, R. Mirgazov, R. Monkhoev, E. Osipova, A. Pakhorukov, L. Pankov, A. Pan, A. Panov, A. Petrukhin, I. Poddubnyi, D. Podgrudkov, V. Poleschuk, V. Ponomareva, E. Popova, E. Postnikov, V. Prosin, V. Ptuskin, A. Pushnin, R. Raikin, A. Razumov, G. Rubtsov, E. Ryabov, Y. Sagan, V. Samoliga, A. Satyshev, A. Silaev, A. Silaev, A. Sidorenkov, A. Skurikhin, A. Sokolov, L. Sveshnikova, V. Tabolenko, L. Tkachev, A. Tanaev, M. Ternovoy, R. Togoo, N. Ushakov, A. Vaidyanathan, P. Volchugov, N. Volkov, D. Voronin, A. Zagorodnikov, D. Zhurov, I. Yashin

  SciPost Phys. Proc. 13, 011 (2023) · published 28 September 2023 | Toggle abstract · pdf

  The Tunka-Grande experiment is a scintillation array with about 0.5 km$^2$ sensitive area at Tunka Valley, Siberia, for measuring charged particles and muons in extensive air showers (EASs). Tunka-Grande is optimized for cosmic ray studies in the energy range 10 PeV to about 1 EeV, where exploring the composition is of fundamental importance for understanding the transition from galactic to extragalactic origin of cosmic rays. This paper attempts to provide a synopsis of the current results of the experiment. In particular, the reconstruction of the all-particle energy spectrum in the range of 10 PeV to 1 EeV based on experimental data from four observation seasons is presented.

  1 citation

• Double Virtual Contributions for Massless 2 -> 3 Scattering in NNLO QCD

  Vasily Sotnikov

  SciPost Phys. Proc. 7, 002 (2022) · published 20 June 2022 | Toggle abstract · pdf

  We review the recent advances in the calculation of two-loop QCD corrections for massless five-point scattering that paved the way for their broad phenomenological applications in calculation of NNLO QCD predictions. We first discuss the construction of a transcendental function basis which facilitates derivation of compact analytic representations for two-loop amplitudes and enables their fast and stable numerical evaluation over physical phase space. We then present the recent calculations of the leading-color two-loop corrections for hadroproduction of three photons and three jets.

  1 citation

• Centre vortex structure of QCD-vacuum fields and confinement

  Derek Leinweber, James Biddle, Waseem Kamleh

  SciPost Phys. Proc. 6, 004 (2022) · published 31 May 2022 | Toggle abstract · pdf

  The non-trivial ground-state vacuum fields of QCD form the foundation of matter. Using modern visualisation techniques, this presentation examines the microscopic structure of these fields. Of particular interest are the centre vortices identified within the ground-state fields of lattice QCD. Our current focus is on understanding the manner in which dynamical fermions in the QCD vacuum alter the centre-vortex structure. The impact of dynamical fermions is significant and provides new insights into the role of centre vortices in underpinning both confinement and dynamical chiral symmetry breaking in QCD.

  1 citation

• Dark Matter phenomenology in 2HDMS

  Gudrid Moortgat-Pick, Juhi Dutta, Cheng Li, Merle Schreiber, Sheikh F. Tabira, Julia Ziegler

  SciPost Phys. Proc. 12, 072 (2023) · published 6 September 2023 | Toggle abstract · pdf

  The constituents of dark matter are still an unresolved puzzle. Several Beyond Standard Model (BSM) Physics offer suitable candidates. In this study here we consider the Two Higgs Doublet model augmented with a complex scalar singlet (2HDMS) and focus on the dark matter phenomenology of 2HDMS with the complex scalar singlet as the dark matter candidate. The parameter space allowed from existing experimental constraints from dark matter, flavour physics and collider searches has been studied. The discovery potential for such a 2HDMS at HL-LHC and at future $e^+e^-$ colliders has been worked out.

  1 citation

• Higher spin swampland conjecture for massive AdS$_{3}$ gravity

  Rajae Sammani, El Hassan Saidi

  SciPost Phys. 18, 173 (2025) · published 3 June 2025 | Toggle abstract · pdf

  In this paper, we show that a possible version of the swampland weak gravity conjecture for higher spin (HS) massive topological AdS$_{3}$ gravity can be expressed in terms of mass M$_{\mathrm{hs}}$, charge Q$_{\mathrm{hs}}$ and coupling constant ${\large g}_{\mathrm{hs}}$ of 3D gravity coupled to higher spin fields as M$_{\mathrm{hs}}≤ \sqrt{2}$Q$_{\mathrm{hs}}{\large g}_{\mathrm{hs}}M_{\mathrm{Pl}}$. The higher spin charge is given by the $SO(1,2)$ quadratic Casimir Q$_{\mathrm{hs}}^{2}=s\left( s-1\right) $ and the HS coupling constant by ${\large g}_{\mathrm{hs}}^{2}=2/\left( M_{\mathrm{Pl}}^{2}l_{\mathrm{AdS}_{3}}^{2}\right) $ while the mass expressed like $\left( l_{\mathrm{AdS}_{3}}\text{M}_{\mathrm{hs}}\right) ^{2}$ is defined as $\left( 1+\mathrm{\mu }l_{\mathrm{AdS}_{3}}\right) ^{2}s\left( s-1\right) +\left[1-\left( \mathrm{\mu }l_{\mathrm{AdS}_{3}}\right) ^{2}\left( s-1\right) \right]$.

  1 citation

• SU(3) hybrid static potentials at small quark-antiquark separations from fine lattices

  Carolin Schlosser, Marc Wagner

  SciPost Phys. Proc. 6, 009 (2022) · published 31 May 2022 | Toggle abstract · pdf

  We summarize our recent lattice gauge theory computation of the $\Pi_u$ and $\Sigma_u^-$ hybrid static potentials at small quark-antiquark separations. We provide parameterizations of the resulting lattice data points, which can be used for investigating masses and properties of heavy hybrid mesons in the Born-Oppenheimer approximation.

  1 citation