Publications

Order by: publication date number of citations

• Density scaling of generalized Lennard-Jones fluids in different dimensions

  Thibaud Maimbourg, Jeppe C. Dyre, Lorenzo Costigliola

  SciPost Phys. 9, 090 (2020) · published 22 December 2020 | Toggle abstract · pdf

  Liquids displaying strong virial-potential energy correlations conform to an approximate density scaling of their structural and dynamical observables. These scaling properties do not extend to the entire phase diagram, in general. The validity of the scaling can be quantified by a correlation coefficient. In this work a simple scheme to predict the correlation coefficient and the density-scaling exponent is presented. Although this scheme is exact only in the dilute gas regime or in high dimension d, the comparison with results from molecular dynamics simulations in d = 1 to 4 shows that it reproduces well the behavior of generalized Lennard-Jones systems in a large portion of the fluid phase.

  6 citations

• Hidden-orders of uranium compounds

  Hisatomo Harima

  SciPost Phys. Proc. 11, 006 (2023) · published 5 June 2023 | Toggle abstract · pdf

  Hidden order is often discussed in strongly correlated electron systems. In many cases, it shows no magnetic responses, so that the order parameter is electric, but accompanies few lattice distortion. In the Jahn-Teller cases, the ordered state gains its energy by changing inter-site mixing strengths, leading a larger structural distortion with lowering symmetry. On the contrary, in strongly correlated electron systems, the strong intra-site Coulomb energy causes the the symmetry lowering. It is not necessary to bring the lattice distortion for lowering local site symmetry. In fact, lower symmetry of electronic state than the symmetry of the crystal structure can be found for UTe$_2$, UGe$_2$ similarly for URu$_2$Si$_2$.

  6 citations

• Quantum many-body simulations with PauliStrings.jl

  Nicolas Loizeau, J. Clayton Peacock, Dries Sels

  SciPost Phys. Codebases 54 (2025) · published 24 March 2025 | Toggle abstract · pdf

  We present the Julia package PauliStrings.jl for quantum many-body simulations, which performs fast operations on the Pauli group by encoding Pauli strings in binary. All of the Pauli string algebra is encoded into low-level logic operations on integers, and is made efficient by various truncation methods which allow for systematic extrapolation of the results. We illustrate the effectiveness of our package by (i) performing Heisenberg time evolution through direct numerical integration and (ii) by constructing a Liouvillian Krylov space. We benchmark the results against tensor network methods, and we find our package performs favorably. In addition, we show that this representation allows for easy encoding of any geometry. We present results for chaotic and integrable spin systems in 1D as well as some examples in 2D. Currently, the main limitations are the inefficiency of representing non-trivial pure states (or other low-rank operators), as well as the need to introduce dissipation to probe long-time dynamics.

  6 citations

• Higher-point integrands in $\mathcal{N} = 4$ super Yang-Mills theory

  Till Bargheer, Thiago Fleury, Vasco Gonçalves

  SciPost Phys. 15, 059 (2023) · published 10 August 2023 | Toggle abstract · pdf

  We compute the integrands of five-, six-, and seven-point correlation functions of twenty-prime operators with general polarizations at the two-loop order in $\mathcal{N}=4$ super Yang-Mills theory. In addition, we compute the integrand of the five-point function at three-loop order. Using the operator product expansion, we extract the two-loop four-point function of one Konishi operator and three twenty-prime operators. Two methods were used for computing the integrands. The first method is based on constructing an ansatz, and then numerically fitting for the coefficients using the twistor-space reformulation of $\mathcal{N}=4$ super Yang-Mills theory. The second method is based on the OPE decomposition. Only very few correlator integrands for more than four points were known before. Our results can be used to test conjectures, and to make progresses on the integrability-based hexagonalization approach for correlation functions.

  6 citations

• Non-Abelian symmetry-resolved entanglement entropy

  Eugenio Bianchi, Pietro Dona, Rishabh Kumar

  SciPost Phys. 17, 127 (2024) · published 5 November 2024 | Toggle abstract · pdf

  We introduce a mathematical framework for symmetry-resolved entanglement entropy with a non-Abelian symmetry group. To obtain a reduced density matrix that is block-diagonal in the non-Abelian charges, we define subsystems operationally in terms of subalgebras of invariant observables. We derive exact formulas for the average and the variance of the typical entanglement entropy for the ensemble of random pure states with fixed non-Abelian charges. We focus on compact, semisimple Lie groups. We show that, compared to the Abelian case, new phenomena arise from the interplay of locality and non-Abelian symmetry, such as the asymmetry of the entanglement entropy under subsystem exchange, which we show in detail by computing the Page curve of a many-body system with $SU(2)$ symmetry.

  6 citations

• An introduction to the surface code

  Andrew N. Cleland

  SciPost Phys. Lect. Notes 49 (2022) · published 3 May 2022 | Toggle abstract · pdf

  This chapter provides an introduction to the surface code, discussing details about how physical qubits are connected and operated to create logical qubits, how errors are handled, and what performance metrics are needed to generate logical qubits with performance that exceeds their underlying physical qubit performance.

  6 citations

• Determination of the rapidity evolution kernel from Drell-Yan data at low transverse momenta

  F. Hautmann, I. Scimemi, A. Vladimirov

  SciPost Phys. Proc. 8, 123 (2022) · published 13 July 2022 | Toggle abstract · pdf

  We report recent results on the extraction of the rapidity evolution kernel for Sudakov processes from experimental measurements of Drell-Yan (DY) transverse momentum distributions. We discuss the role of high-precision Large Hadron Collider (LHC) data, and illustrate the interplay of this analysis with transverse momentum dependent and collinear parton density functions.

  6 citations

• The impact of non-ideal surfaces on the solid-water interaction: a time-resolved adsorption study

  Matthias M. May, Helena Stange, Jonas Weinrich, Thomas Hannappel, Oliver Supplie

  SciPost Phys. 6, 058 (2019) · published 13 May 2019 | Toggle abstract · pdf

  The initial interaction of water with semiconductors determines the electronic structure of the solid-liquid interface. The exact nature of this interaction is, however, often unknown. Here, we study gallium phosphide-based surfaces exposed to H2O by means of in situ reflection anisotropy spectroscopy. We show that the introduction of typical imperfections in the form of surface steps or trace contaminants not only changes the dynamics of the interaction, but also its qualitative nature. This emphasises the challenges for the comparability of experiments with (idealised) electronic structure models for electrochemistry.

  6 citations

• Spin conductivity of the XXZ chain in the antiferromagnetic massive regime

  Frank Göhmann, Karol K. Kozlowski, Jesko Sirker, Junji Suzuki

  SciPost Phys. 12, 158 (2022) · published 12 May 2022 | Toggle abstract · pdf

  We present a series representation for the dynamical two-point function of the local spin current for the XXZ chain in the antiferromagnetic massive regime at zero temperature. From this series we can compute the correlation function with very high accuracy up to very long times and large distances. Each term in the series corresponds to the contribution of all scattering states of an even number of excitations. These excitations can be interpreted in terms of an equal number of particles and holes. The lowest term in the series comprises all scattering states of one hole and one particle. This term determines the long-time large-distance asymptotic behaviour which can be obtained explicitly from a saddle-point analysis. The space-time Fourier transform of the two-point function of currents at zero momentum gives the optical spin conductivity of the model. We obtain highly accurate numerical estimates for this quantity by numerically Fourier transforming our data. For the one-particle, one-hole contribution, equivalently interpreted as a two-spinon contribution, we obtain an exact and explicit expression in terms of known special functions. For large enough anisotropy, the two-spinon contribution carries most of the spectral weight, as can be seen by calculating the f-sum rule.

  6 citations

• Evidence of $\phi_0$-Josephson junction from skewed diffraction patterns in Sn-InSb nanowires

  B. Zhang, Z. Li, V. Aguilar, P. Zhang, M. Pendharkar, C. Dempsey, J. S. Lee, S. D. Harrington, S. Tan, J. S. Meyer, M. Houzet, C. J. Palmstrom, S. M. Frolov

  SciPost Phys. 18, 013 (2025) · published 13 January 2025 | Toggle abstract · pdf

  We study Josephson junctions based on InSb nanowires with Sn shells. We observe skewed critical current diffraction patterns: the maxima in forward and reverse current bias are at different magnetic flux, with a displacement of 20-40 mT. The skew is greatest when the external field is nearly perpendicular to the nanowire, in the substrate plane. This orientation suggests that spin-orbit interaction plays a role. We develop a phenomenological model and perform tight-binding calculations, both methods reproducing the essential features of the experiment. The effect modeled is the $\phi_0$-Josephson junction with higher-order Josephson harmonics. The system is of interest for Majorana studies: the effects are either precursor to or concomitant with topological superconductivity. Current-phase relations that lack inversion symmetry can also be used to design quantum circuits with engineered nonlinearity.

  6 citations