Publications

Order by: publication date number of citations

• New directions in the search for dark matter

  Surjeet Rajendran

  SciPost Phys. Lect. Notes 56 (2022) · published 23 May 2022 | Toggle abstract · pdf

  The identification of the nature of dark matter is one of the most important problems confronting particle physics. Current observational constraints permit the mass of the dark matter to range from $\sim 10^{-22}$ eV - $10^{48}$ GeV. Given the weak nature of these bounds and the ease with which dark matter models can be constructed, it is clear that the problem can only be solved experimentally. In these lectures, I discuss methods to experimentally probe a wide range of dark matter candidates.

  5 citations

• Quantum enhanced metrology in the search for fundamental physical phenomena

  Konrad W. Lehnert

  SciPost Phys. Lect. Notes 40 (2022) · published 11 March 2022 | Toggle abstract · pdf

  These notes summarize lectures given at the 2019 Les Houches summer school on Quantum Information Machines. They describe and review an application of quantum metrology concepts to searches for ultralight dark matter. In particular, for ultralight dark matter that couples as a weak classical force to a laboratory harmonic oscillator, quantum squeezing benefits experiments in which the mass of the dark matter particle is unknown. This benefit is present even if the oscillatory dark matter signal is much more coherent than the harmonic oscillator that it couples to, as is the case for microwave frequency searches for dark matter axion particles.

  4 citations

• From classical to quantum regime of topological surface states via defect engineering

  Maryam Salehi, Xiong Yao, Seongshik Oh

  SciPost Phys. Lect. Notes 58 (2022) · published 21 July 2022 | Toggle abstract · pdf

  Since the notion of topological insulator (TI) was envisioned in late 2000s, topology has become a new paradigm in condensed matter physics. Realization of topology as a generic property of materials has led to numerous predictions of topological effects. Although most of the classical topological effects, directly resulting from the presence of the spin-momentum-locked topological surface states (TSS), were experimentally confirmed soon after the theoretical prediction of TIs, many topological quantum effects remained elusive for a long while. It turns out that native defects, particularly interfacial defects, have been the main culprit behind this impasse. Even after quantum regime is achieved for the bulk states, TSS still tends to remain in the classical regime due to high density of interfacial defects, which frequently donate mobile carriers due to the very nature of the topologically-protected surface states. However, with several defect engineering schemes that suppress these effects, a series of topological quantum effects have emerged including quantum anomalous Hall effect, quantum Hall effect, quantized Faraday/Kerr rotations, topological quantum phase transitions, axion insulating state, zeroth-Landau level state, etc. Here, we review how these defect engineering schemes have allowed topological surface states to pull out of the murky classical regime and reveal their elusive quantum signatures, over the past decade.

  4 citations

• Four lectures on Euler integrals

  Saiei-Jaeyeong Matsubara-Heo, Sebastian Mizera, Simon Telen

  SciPost Phys. Lect. Notes 75 (2023) · published 26 October 2023 | Toggle abstract · pdf

  These lecture notes provide a self-contained introduction to Euler integrals, which are frequently encountered in applications. In particle physics, they arise as Feynman integrals or string amplitudes. Our four selected topics demonstrate the diverse mathematical techniques involved in the study of Euler integrals, including polyhedral geometry, very affine varieties, differential equations, and computational algebra.

  4 citations

• Quantum to classical mapping of the two-dimensional toric code in an external field

  Sydney R. Timmerman, Zvonimir Z. Bandic, Roger G. Melko

  SciPost Phys. Lect. Notes 57 (2022) · published 20 July 2022 | Toggle abstract · pdf

  Kitaev's toric code Hamiltonian in dimension D=2 has been extensively studied for its topological properties, including its quantum error correction capabilities. While the Hamiltonian is quantum, it lies within the class of models that admits a D+1 dimensional classical representation. In these notes, we provide details of a Suzuki-Trotter expansion of the partition function of the toric code Hamiltonian in the presence of an external magnetic field. By coupling additional degrees of freedom in the form of a matter field that can subsequently be gauged away, we explicitly derive a classical Hamiltonian on a cubic lattice which takes the form of a non-isotropic 3D Ising gauge theory.

  3 citations

• Plea for the use of the exact Stirling formula in statistical mechanics

  Didier Lairez

  SciPost Phys. Lect. Notes 76 (2023) · published 30 October 2023 | Toggle abstract · pdf

  In statistical mechanics, the generally called Stirling approximation is actually an approximation of Stirling's formula. In this article, it is shown that the term that is dropped is in fact the one that takes fluctuations into account. The use of the Stirling's exact formula forces us to reintroduce them into the already proposed solutions of well-know puzzles such as the extensivity paradox or the Gibbs' paradox of joining two volumes of identical gas. This amendment clearly results in a gain in consistency and rigor of these solutions.

  3 citations

• SIMP Dark Matter

  Yonit Hochberg

  SciPost Phys. Lect. Notes 59 (2022) · published 29 July 2022 | Toggle abstract · pdf

  These notes summarize the zoom-course on Strongly Interacting Massive Particle (SIMP) dark matter given at the Les Houches Summer School in the summer of 2021. An alternative title for this course would be `SIMPS, Cannibals and ELDERs', where our focus is on high-point interactions amongst dark matter particles. The spirit of the course is to give students a taste of these exciting developments in dark matter, while primarily teaching tricks and methods that are tough to captivate when reading textbooks or papers. These notes are written in similar spirit: I will put emphasis on how quantities scale and how to perform back of the envelope estimates, which should serve to help you when you develop the next great dark matter idea.

  3 citations

• Aspects of 4d supersymmetric dynamics and geometry

  Shlomo S. Razamat, Evyatar Sabag, Orr Sela, Gabi Zafrir

  SciPost Phys. Lect. Notes 78 (2024) · published 12 February 2024 | Toggle abstract · pdf

  In this set of five Lectures we present a basic toolbox to discuss the dynamics of four dimensional supersymmetric quantum field theories. In particular we overview the program of geometrically engineering the four dimensional supersymmetric models as compactifications of six dimensional SCFTs. We discuss how strong coupling phenomena in four dimensions, such as duality and emergence of symmetry, can be naturally imbedded in the geometric constructions. The Lectures mostly review results which previously appeared in the literature but also contain some unpublished derivations.

  3 citations

• Introduction to Monte Carlo for matrix models

  Raghav G. Jha

  SciPost Phys. Lect. Notes 46 (2022) · published 4 April 2022 | Toggle abstract · pdf

  We consider a wide range of matrix models and study them using the Monte Carlo technique in the large N limit. The results we obtain agree with exact analytic expres- sions and recent numerical bootstrap methods for models with one and two matrices. We then present new results for several unsolved multi-matrix models where no other tool is yet available. In order to encourage an exchange of ideas between different numerical approaches to matrix models, we provide programs in Python that can be easily modified to study potentials other than the ones discussed. These programs were tested on a laptop and took between a few minutes to several hours to finish depending on the model, N, and the required precision.

  3 citations

• Lectures in quantum gravity

  Ivano Basile, Luca Buoninfante, Francesco Di Filippo, Benjamin Knorr, Alessia Platania, Anna Tokareva

  SciPost Phys. Lect. Notes 98 (2025) · published 7 August 2025 | Toggle abstract · pdf

  Formulating a quantum theory of gravity lies at the heart of fundamental theoretical physics. This collection of lecture notes encompasses a selection of topics that were covered in six mini-courses at the Nordita PhD school "Towards Quantum Gravity". The scope was to provide a coherent picture, from its foundation to forefront research, emphasizing connections between different areas. The lectures begin with perturbative quantum gravity and effective field theory. Subsequently, two ultraviolet-complete approaches are presented: Asymptotically safe gravity and string theory. Finally, elements of quantum effects in black hole spacetimes are discussed.

  3 citations