## May 2, 2019, 3:30 p.m.

Casimir room## Hadrons under extreme conditions

Gert Aarts

Heavy-ion collisions investigate the strong force under the extreme conditions of high temperature and vanishing or small baryon density. While the quark-gluon plasma has been studied theoretically in great detail, the hadronic gas at lower temperatures is usually described using effective low-energy models. Here I'll report on work of the FASTSUM collaboration which aims to give a first-principle description at all temperatures, using lattice QCD simulations both below and above the deconfinement transition. Particular attention is given to baryons and to spectral changes at small but nonzero baryon chemical potential.## May 6, 2019, 2 p.m.

Casimir room## Slow quenches in topological insulators

Lara Ulcakar

## May 8, 2019, 3:30 p.m.

Casimir room## Primordial Black Holes during Inflation and the Non-Gaussian Regime

Vicente Atal

Primordial Black Holes (PBH) could be formed during inflation, possibly giving account for the dark matter in the Universe. The mass and abundances of the PBH depends on the shape of the collapsed regions as well as the statistics of the underlying random density field. These are usually determined assuming gaussian statistics for the inflaton perturbations. In this talk, I will show that this approximation fails for all single field models of inflation producing PBH known so far in the litterature. I will argue that a non-perturbative calculation of the non-gaussianities is necessary and present recent developments in this direction.## May 9, 2019, 3:30 p.m.

Casimir room## Eigenstate thermalization in the Sachdev-Ye-Kitaev model

Manuel Vielma

The eigenstate thermalization hypothesis (ETH) proposes an explanation as to how closed unitary quantum systems can exhibit thermal behavior in pure states. In this work we examine the Sachdev-Ye-Kitaev model as well its IR limit as described by an effective Schwarzian action. We show that, as expected from evidence found using exact diagonalization, the model satisfies ETH. In the Schwarzian limit, we study a specific class of states created by heavy operators and find that they only show a weak form of ETH. Based on arXiv:1707.08013 (with J. Sonner), arXiv:1903.00478 (with P. Nayak and J. Sonner) and work in progress (with P. Nayak and J. Sonner)## May 13, 2019, 11:30 a.m.

Casimir room## Electronic states of pseudospin-1 fermions in lattice ribbons in a magnetic field

Dima Oriekhov

## May 22, 2019, 11:30 a.m.

Casimir room## Vacancies in Graphene : Dirac Physics and Fractional Vacuum Charges

Omrie Ovdat

## May 22, 2019, 3:30 p.m.

Casimir room## Probing the Physics of the Early Universe with Gravitational Interferometers

Gianmassimo Tasinato

Cosmological inflation predicts the existence of a stochastic background of gravitational waves, whose features depend on the model of inflation under consideration. There exist well motivated frameworks predicting an enhancement of the primordial gravity wave spectrum at frequency scales testable with gravitational wave experiments, with distinctive features as parity violation and non-Gaussianity. I will explain the properties of such scenarios, and their distinctive predictions for what respect the gravity wave power spectrum and bispectrum. I will then discuss how to quantitatively test these predictions with current and future interferometers.## May 22, 2019, 7:30 p.m.

Sitterzaal## The second kind of impossible

Paul Steinhardt

Quasicrystals are exotic forms of matter with symmetries that were once thought to be mathematically impossible. The first known examples were synthesized in the laboratory over 35 years ago, but could Nature have beaten us to the punch? This talk will describe the decades-long search to answer this question, resulting in one of the strangest scientific stories you are ever likely to hear.## May 28, 2019, 1 p.m.

Casimir room## What use are the Baryon Acoustic Oscillations? Why the Linear Point standard ruler?

Stefano Anselmi

Baryon Acoustic Oscillations (BAO) are one of the most useful and used cosmological probes to measure cosmological distances independently of the underlying background cosmology. However, in the current measurements, the inference is done using a theoretical clustering correlation function template where the cosmological and the non-linear damping parameters are kept fixed to fiducial LCDM values. How can we then claim that the measured distances are model-independent and so useful to select cosmological models? Motivated by this compelling question we introduce a rigorous tool to measure cosmological distances without assuming a specific background cosmology: the â€œPurely-Geometric-BAOâ€. I will explain how to practically implement this tool with clustering data. This allows us to quantify the effects of the standard measurementsâ€™ assumptions. I will then focus on a new approach to the problem that leverages a novel BAO cosmological standard ruler: the â€œLinear Pointâ€. Its standard ruler properties allow us to estimate cosmological distances without the need of modeling the poorly-known late-time nonlinear corrections to the linear correlation function. Last but not least, it also provides smaller statistical uncertainties with respect to the correlation function template fit.## June 5, 2019, 11:30 a.m.

Casimir room## Coherent electrical control of a single high spin nucleus in silicon

Vincent Mourik

Nuclear electric resonance (NER) enables transitions of a high spin nucleus by modulating its electrical quadrupole interaction with an electric field. In this talk I will show how we found this effect in our single 123-Sb donor device in silicon, with nuclear spin of size 7/2. We demonstrate, for the first time, coherent, purely electrical control of a single high spin nucleus. I will share our theoretical understanding of the microscopic mechanism at play in our device, based on analytical approximations, density functional theory calculations and finite element simulations. Finally, I will discuss future research directions exploiting this versatile system.## June 5, 2019, 7:30 p.m.

Sitterzaal## Quantum computing past, present, and future

Seth Lloyd

Quantum computers store and process information at the level of individual atoms, photons, and spins. The strange and counter-intuitive nature of quantum mechanics allows quantum computers to perform computations in ways that classical computers can't. This talk reviews the history of quantum computing, including how they can be constructed, and why quantum algorithms give exponential speed ups over their classical counterparts. The talk presents the current state of the art in experimental realizations of quantum computers and quantum algorithms, and discusses various possible futures for quantum information processing.## June 6, 2019, 11:30 a.m.

Casimir room## Large contribution of Fermi arcs to the conductivity of Weyl metals

Maxim Breitkreiz

## June 11, 2019, 2 p.m.

De Sitterzaal## Quantum computing: past, present, and future: Lecture 1

Seth Lloyd

## June 18, 2019, 2 p.m.

De Sitterzaal## Quantum computing: past, present, and future: Lecture 2

Seth Lloyd

## June 19, 2019, 10 a.m.

Casimir room## Applications of Information Theory to Cosmology

Ana Marta Pinho

Although there is still a strong statistical preference for the LCDM model, a few data discrepancies have recently emerged. These discrepancies or tensions raise the doubt about the data pipeline and/or the LCDM model assumption. Information theory yields some useful tools to measure the amount of information present in the data. These tools can be related to the commonly used as uncertainty measurements in statistical inference. In this talk, I will present the lastest results of this ongoing work that tries to get a different perspective on the available cosmological information.## June 19, 2019, noon

Casimir room## Some features of KdV partition functions for c > 1 CFTs

Diptarka Das

It can be shown that for 2d conformal field theories with just two copies of Virasoro symmetry, infinite conserved charges of the Korteweg-de Vries (KdV) hierarchy can be constructed by relating to the quantum sinh-Gordon model. This naturally generalizes the torus partition function / thermal ensemble to a Generalized Gibbs Ensemble (GGE). In the large central charge limit, we will approximate the characters appearing in the GGE and investigate possible transformation properties under generalized modular transformations.## June 25, 2019, 2 p.m.

De Sitterzaal## Quantum computing: past, present, and future: Lecture 3

Seth Lloyd

## June 27, 2019, 1 p.m.

Gorterzaal## A Tip for Landscape Riders: Multi-Field Inflation Can Fulfill the Swampland Distance Conjecture

Simon Dario Riquelme Munoz

We study how both the swampland distance conjecture and the Lyth bound affect the parameter space of multi-field models of inflation. A generic feature of multi-field inflation is that the geodesic distance $\left[\Delta\phi\right]_\text{G}$ separating any two points laying along the inflationary trajectory differs from the non-geodesic distance $\left[\Delta\phi\right]_\text{NG}$ traversed by the inflaton between those points. These distances must respect a relation of the form $\left[\Delta\phi\right]_\text{G} = f\left(\left[\Delta\phi\right]_\text{NG}\right) \leq \left[\Delta\phi\right]_\text{NG}$, where $f$ is a function determined by the specific multi-field model under scrutiny. We show that this relation leads to important constraints on the parameter space characterizing the multi-field dynamics. Indeed, the swampland distance conjecture implies an upper bound on $\left[\Delta\phi\right]_\text{G}$ set by the details of the ultraviolet completion of inflation, whereas the Lyth bound implies a lower bound on $\left[\Delta\phi\right]_\text{NG}$ determined by the value of the tensor-to-scalar ratio. If future observations confirm the existence of primordial tensor perturbations, these two bounds combined lead to tight constraints on the possible values of the entropy mass of the isocurvature fields orthogonal to the inflationary trajectory and the rate of turn of the inflationary trajectory in multi-field space. We analyze the emerging constraints in detail for the particular case of two-field inflation in hyperbolic field spaces.## July 11, 2019, 1 p.m.

Casimir room## Constraining the nature of dark matter with the Lyman-alpha forest

Antonella Garzilli

We review how the Lyman-alpha forest, one of the observables of the intergalactic medium, can be used to constrain the free-streaming length of dark matter particles. We analyse old and new data-sets of high redshift and high resolution Lyman-alpha forest spectra: the observed Lyman-alpha flux power spectrum (FPS) is suppressed on scales below ~ 30 km/s. This cutoff could be due to the high temperature and pressure of the absorbing gas or, alternatively, it could reflect the free streaming of dark matter particles in the early universe. We perform a set of very high resolution cosmological hydrodynamic simulations, and compare the FPS of mock spectra to the data. We demonstrate that the FPS cutoff can be fit assuming cold dark matter, but it can be equally well fit assuming that the dark matter consists of ~7 keV sterile neutrinos in which case the cutoff is due primarily to the dark matter free streaming.## July 16, 2019, 10 a.m.

Casimir room## TBD

Chiara Moretti

## Aug. 30, 2019, 4 p.m.

Gratama room, Lorentz Center## Golden Jubilee

Professor Hans van Leeuwen

16:00 Carlo Beenakker: Welcome Wim van Saarloos - Hans van Leeuwen and Statistical Physics, 50+ years of contributions Daniel Bonn - The Physics of Ice Skating Henk Lekkerkerker - CO2 Friend of Foe 17.30 reception- Aug. 30, 2019, 4 p.m. Professor Hans van Leeuwen (Instituut-Lorentz) Golden Jubilee
## Sept. 25, 2019, 7:30 p.m.

Sitterzaal## TBA

François Graner

TBA- Sept. 25, 2019, 7:30 p.m. CE François Graner (Paris Diderot University) TBA
## Oct. 2, 2019, 7:30 p.m.

Sitterzaal## TBA

Christopher Jarzynski

TBA- Oct. 2, 2019, 7:30 p.m. CE Christopher Jarzynski (University of Maryland) TBA
## Nov. 6, 2019, 7:30 p.m.

Sitterzaal## TBA

Jo van den Brand

TBA- Nov. 6, 2019, 7:30 p.m. CE Jo van den Brand (Nikhef/Virgo) TBA

LS = Lorentz Seminar, Casimir room (276), Oort building

CE = Colloquium Ehrenfestii, De Sitter lecture room, Oort building

SBM = Soft & Biological Matter Seminar, Casimir room (276), Oort building

CS = Cosmology Seminar, Casimir room (276), Oort building

ST = String Theory Seminar, Casimir room (276), Oort building