Thema: 
Soft Pions and the Dynamics of the Chiral Phase Transition 
Datum: 
11.07.22 
Uhrzeit: 
16:15 
Ort: 
Y0111 
Vortragender: 

Stony Brook University 

Inhalt: 
I will first review lattice simulations of the QCD phase diagram, focusing on chiral symmetry and chiral symmetry breaking. In the limit of two massless quark flavors (up and down) the chiral phase transition is second order and is in the O(4) universality class. The fingerprints of this critical point are seen in lattice simulations of real world QCD. Next I will review heavy ion experiments, presenting an overview of some of the most important measurements from heavy ion collisions. These measurements provide compelling evidence that classical hydrodynamics is an appropriate effective theory for understanding these collisions. In current hydrodynamic simulations of these events, chiral symmetry breaking and its consequences are largely ignored. However, if the quark mass is small enough, one would expect that the pattern of chiral symmetry breaking seen on the lattice could provide a useful organizing principle for hydrodynamics, increasing its predictive power. I describe our efforts to simulate the real time dynamics of the O(4) critical point using hydrodynamics. Then I point out some discrepancies between the measured yields of soft pions and current hydrodynamic simulations. I suggest that incorporating the chiral phase transition into the hydrodynamic description could fix the discrepancies. 
Ansprechpartner: 
Thema: 
Vertex Algebras for 2 and 4Dimensional Conformal Field Theories 
Datum: 
01.07.22 
Uhrzeit: 
16:15 
Ort: 
D5153 
Vortragender: 

Universität Hamburg 

Inhalt: 
Vertex (operator) algebras axiomatise 2dimensional conformal field theories in physics. They were introduced in the 1980s to explain mysterious connections between number and representation theory (monstrous moonshine). Not long ago, they were also shown to capture certain aspects of 4dimensional superconformal field theories. In this talk I will describe recent classification results for holomorphic vertex algebras of central charge 24 by means of certain modular forms (vectorvalued Eisenstein series). Moreover, I will sketch classification problems arising in the context of 4dimensional field theories. 
Ansprechpartner: 
Thema: 
Schwinger Model at Finite Temperature and Density with Beta VQE 
Datum: 
16.08.22 
Uhrzeit: 
14:15 
Ort: 
D6135 
Vortragender: 

International Professional University of Technology in Osaka 

Inhalt: 
We investigate a quantum gauge theory at finite temperature and density using a variational algorithm for nearterm quantum devices. We adapt ?VQE to evaluate thermal and quantum expectation values and study the phase diagram for massless Schwinger model along with the temperature and density. By compering the exact variational free energy, we find the variational algorithm work for T>0 and ?>0 for the Schwinger model. No significant volume dependence of the variational free energy is observed in ?/g?[0,1.4]. We calculate the chiral condensate and take the continuum extrapolation. As a result, we obtain qualitative picture of the phase diagram for massless Schwinger model. 
Ansprechpartner: 
Thema: 
9.00  16.00: Seminartag FFM@UBI 
Datum: 
19.08.22 
Uhrzeit: 
09:00 
Ort: 
D5153 
Vortragender: 
4 x FFM + 4 x UBI 
FFM & UBI 

Inhalt: 
Das wird ein großartiger Seminartag. 
Ansprechpartner: 
Thema: 
Manyparticles diffusing with resetting: study of the largedeviation properties of the flux distribution 
Datum: 
05.05.22 
Uhrzeit: 
16:00 
Ort: 
D5153 
Vortragender: 
Costantino Di Bello 
Inhalt: 
In this paper we studied a model of noninteracting particles moving on a line following a common dynamics. In particular we considered either a diffusive motion with Poissonian resetting, and a runandtumble motion with Poissonian resetting. We were interested in studying the distribution of the random variable $Q_t$ defined as the flux of particles through origin up to time $t$. We used the notation $P(Q,t)$ to identify the probability $\mathbb{P}\{Q_t=Q\}$. We considered particles initially located on the negative half line with a fixed density $\rho$. In fully analogy with disordered systems, we studied both the annealed and the quenched case for initial conditions. In the former case we found that, independently from the specific dynamics, $P_\mathrm{an}(Q,t)$ has a Poissonian shape; while in the latter case, for what concerns the diffusive dynamics with resetting, the large deviation form of the quenched distribution reads $P_\mathrm{qu}(Q,t)\sim \exp\left[r^2t^2 \Psi_\mathrm{diff}\left(\dfrac{Q}{\rho t}\right)\right]$ with the large deviation function $\Psi_\mathrm{diff}(x)$ exhibiting a discontinuity in the third derivative, hence aiming, despite the simplicity of the model, at the exhistence of a dynamical phase transition. The quenched distribution for the runandtumble dynamics, instead, does not exhibit any kind of phase transition. Importance sampling Monte Carlo simulations were performed to prove the analytical results. References: Current fluctuations in noninteracting runandtumble particles in one dimension Tirthankar Banerjee, Satya N. Majumdar, Alberto Rosso, and Grégory Schehr, Phys. Rev. E 101, 052101 https://doi.org/10.1103/PhysRevE.101.052101 Current Fluctuations in One Dimensional Diffusive Systems with a Step Initial Density Profile B. Derrida and A. Gerschenfeld, J. Stat. Phys. 137, 978 (2009) https://doi.org/10.1007/s1095500998301 
Ansprechpartner: 
Thema: 
Multiplicative statistics of random matrices and the integrodifferential Painlevé II equation 
Datum: 
31.08.22 
Uhrzeit: 
09:00 
Ort: 
ZOOM / Konferenzschaltung 
Vortragender: 

Universidade de Sao Paulo 

Inhalt: 
In this talk we consider a large family of multiplicative statistics of eigenvalues of hermitian random matrix models with a onecut regular potential. We show that they converge to an universal multiplicative statistics of the Airy2 point process which, in turn, is described in terms of a particular solution to the integrodifferential Painlevé II equation. The same solution to this integrodifferential equation appeared for the first time in the description of the narrow wedge solution to the KPZ equation, so our results connect the KPZ equation in finite time with random matrix theory in an universal way. The talk is based on joint work with Promit Ghosal (MIT). 
Ansprechpartner: 