Thema: |
Antrittsvorlesung |
Datum: |
23.05.22 |
Uhrzeit: |
16:15 |
Ort: |
H6 |
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Universität Bielefeld |
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Inhalt: |
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Thema: |
tba |
Datum: |
03.06.22 |
Uhrzeit: |
16:15 |
Ort: |
V4-119 |
Vortragender: |
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University of Hamburg |
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Inhalt: |
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Ansprechpartner: |
Thema: |
tba |
Datum: |
30.06.22 |
Uhrzeit: |
14:15 |
Ort: |
D6-135 |
Vortragender: |
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Universität Bern |
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Inhalt: |
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Thema: |
14.00 tba |
Datum: |
03.06.22 |
Uhrzeit: |
14:00 |
Ort: |
ZOOM / Konferenzschaltung |
Vortragender: |
Jakub Mrozek |
University of Oxford |
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Inhalt: |
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Thema: |
Many-particles diffusing with resetting: study of the large-deviation properties of the flux distribution |
Datum: |
05.05.22 |
Uhrzeit: |
16:00 |
Ort: |
D5-153 |
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 run-and-tumble 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 run-and-tumble 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 run-and-tumble 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/s10955-009-9830-1 |
Ansprechpartner: |
Thema: |
Exponential Functional of the Matrix Brownian Motion, Dufresne Identity and Quantum Scattering |
Datum: |
25.05.22 |
Uhrzeit: |
09:00 |
Ort: |
ZOOM / Konferenzschaltung |
Vortragender: |
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LPTMC, Sorbonne Université |
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Inhalt: |
Exponential functionals of the Brownian motion appear in many different contexts (classical diffusion in random media, quantum scattering, finance,...). I will discuss a recent generalization to the case of matrix Brownian motion. This problem has a natural motivation within the study of quantum scattering on a disordered wire with several conducting channels. I will show that the Wigner-Smith time delay matrix, a fundamental matrix in quantum scattering encoding several characteristic time scales, can be represented as an exponential functional of the matrix BM. I will discuss the relation between this problem of quantum physics and the Dufresne identity, which gives the stationary distribution of such exponential functionals of the BM. Ref: Aurélien Grabsch and Christophe Texier, Wigner-Smith matrix, exponential functional of the matrix Brownian motion and matrix Dufresne identity, J. Phys. A: Math. Theor. 53, 425003 (2020) |
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