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Calendar of Physics Talks Vienna
| Relative entropy and dynamical black holes |
| Speaker: | Edoardo DâAngelo (Genoa U. and INFN, Genoa) |
| Abstract: | Since the discovery of the Bekenstein-Hawking formula,there had been many attempts to derive the entropy of black holes from the entanglement between the degrees of freedom inside and outside the event horizon.This entanglement entropy reproduces the area-law,but it suffers from divergences in the continuum limit.In this talk I show how to derive the Bekenstein-Hawking entropy from the relative entropy,which is well-defined also for continuum theories such as QFT,in the case of dynamical,spherically symmetric black holes.I first review the algebraic quantization of a free scalar field on curved space-times,and show how to compute its relative entropy from the initial data at infinity.Using the back-reaction of a free,scalar quantum field on the metric,I show that a variation in the relative entropy between coherent states of the field produces a variation of one-quarter of the black hole |
| Date: | Tue, 14.03.2023 |
| Time: | 14:00 |
| Duration: | 60 min |
| Location: | Erwin-Schroedinger Lecture Hall, Faculty of Physics, Boltzmanngasse 5, 5th floor |
| Contact: | D. Grumiller, S. Fredenhagen, E. Battista, R. Ruzziconi |
| Extending Precision Perturbative QCD with Track Functions |
| Speaker: | Yibei Li (Zhejiang University) |
| Abstract: | Track functions describe the collective effect of the fragmentation of quarks and gluons into charged hadrons, making them a key ingredient for jet substructure measurements at hadron colliders where track-based measurements offer superior angular resolution. Unlike DGLAP,the evolution of track functions incorporates correlations between final-state hadrons,and is hence non-linear. Following our study on the track function evolution in Mellin space and its application to correlations of charged energy flows,we derive the NLO renormalization of the track functions in momentum space in both N=4 SYM and QCD, which are the first example of evolution equations involving the full 1-to-3 splitting functions. We clarify how our evolution equations can be reduced to those for the single- and multi-hadron fragmentation functions, and can hence be viewed as the most general collinear evolution .... |
| Date: | Tue, 14.03.2023 |
| Time: | 16:15 |
| Duration: | 60 min |
| Location: | Erwin-Schroedinger Lecture Hall, Faculty of Physics, Boltzmanngasse 5, 5th floor |
| Contact: | A. Hoang, M. Procura |
| Quantum measurements and equilibration: modelling the emergence of objectivity via entropy maximisation |
| Speaker: | Maximilian Lock (Atominstitut, TU Wien) |
| Abstract: | Textbook quantum physics features two types of dynamics: reversible unitary dynamics and irreversible measurements. The latter stands in conflict with the laws of thermodynamics and has evoked much debate. With the help of modern quantum statistical mechanics, we take the first step in formalising the hypothesis that quantum measurements are instead driven by the natural tendency of closed systems to maximise entropy, a notion that we call the Measurement-Equilibration Hypothesis. In this paradigm, we investigate how objective measurement outcomes can emerge within an purely unitary framework, and find that: (i) the interactions used in standard measurement models fail to spontaneously feature emergent objectivity and (ii) while ideal projective measurements are impossible, we can (for a given form of interaction) approximate them exponentially well as we collect more physical systems to |
| Date: | Wed, 15.03.2023 |
| Time: | 16:15 |
| Duration: | 45 min |
| Location: | Hörsaal ATI only live |
| Contact: | Maximilian Prüfer |
| Equivalence principle in quantum mechanics: different formulations and applications |
| Speaker: | Carlo Cepollaro (OeAW) |
| Abstract: | I will talk about the equivalence principle in quantum mechanics, exploring different ideas that have been proposed in the literature. The classical equivalence principle has various versions and interpretations, which explains the broad literature and diversity of approaches. I will begin by reviewing the different versions of the classical principle, and highlight their role in quantum mechanics. I will then summarize some of the proposals from the literature that suggest that the equivalence principle is incompatible with quantum mechanics, as well as other proposals that extend the principle to include quantum mechanical effects. Finally, I will focus on a recent proposal to extend the equivalence principle by using quantum reference frames, and show how this idea can be tested experimentally. |
| Date: | Thu, 16.03.2023 |
| Time: | 09:30 |
| Duration: | 60 min |
| Location: | Seminarraum EG Atominstitut (Neutronenfrühstück) |
| Contact: | Benjamin Koch |
| Infinite distances in multicritical CFTs and higher-spin holography |
| Speaker: | Andrea Campoleoni (FNRS research associate Université de Mons, Belgium) |
| Abstract: | The swampland distance conjecture states that, approaching an
infinite-distance limit in moduli space in a theory of gravity admitting
an UV completion, asymptotically (i) an infinite tower of states becomes
light and (iii) the masses vanish exponentially. In the AdS/CFT context,
the tower of states is dual to a higher-spin tower of currents and the
exponential decay concerns their anomalous dimensions.
This conjecture has been elaborated from the analysis of examples in
String Theory. In this talk we discuss how one can test it also in
higher-spin gravity, which provides another candidate UV complete theory
of gravity, by exploiting its CFT reformulation. To this end, one can
study multicritical generalizations of large-N vector models, bosonic
and fermionic, and compute the quantum information distance along
selected renormalization-group trajectories toward the higher-spin
limit. |
| Date: | Thu, 16.03.2023 |
| Time: | 13:00 |
| Duration: | 60 min |
| Location: | Fakultaet fuer Physik, Ernst-Mach-HS, Boltzmanngasse 5, 2. Stock |
| Contact: | S. Fredenhagen |
| Retiring the third law of black hole thermodynamics |
| Speaker: | Christopher Kehle (ETH Zürich) |
| Abstract: | In this talk, I will present a rigorous construction of examples of black hole formation which are exactly isometric to extremal Reissner-â-Nordström after finite time.
In particular, our result can be viewed as a definitive disproof of the ``third law of black hole thermodynamics.ââ This is based on joint work with Ryan Unger (Princeton). |
| Date: | Thu, 16.03.2023 |
| Time: | 15:30 |
| Duration: | 60 min |
| Location: | Seminarraum A, Waehringer StraÃe 17, 2. Stock |
| Contact: | P. Chrusciel, D. Fajman |
| Dark matter from confining SO(N)-like gauge theories with two Dirac fermions |
| Speaker: | Joachim Pomper (TU Graz) |
| Abstract: | In this thesis I construct and investigate confining gauge theories in order to look for models realizing the so-called strongly interacting massive particle (SIMP) regime of dark matter. The greatest appeal of these models is that the strong self-interactions between dark matter particles may resolve some problems in structure formation, like the cusp vs. core problem. After a short introduction to SIMPs, I will discuss gauge theories based on two Dirac fermions, transforming
under a real representation of the classical groups, with focus on the symmetries, symmetry breaking and emerging light fermion bounds-states, relevant for dark matter phenomenology. The dynamics of the cold dark matter may be described by a low-energy effective theory, similar to chiral perturbation theory in QCD. For SIMPs, the interactions driving the freeze out process come from 5 point vertices related to ... |
| Date: | Thu, 16.03.2023 |
| Time: | 16:00 |
| Duration: | 50 min |
| Location: | TU Wien, SEM 136 (Wiedner Hauptstrasse 8, 1040 Vienna, Freihaus, 10th floor) |
| Contact: | Florian Ecker and Daniel Grumiller |
| Study of a simple equation that describes the ground-state energy of a Bose gas at low and high density and in dimensions one, two and three |
| Speaker: | Prof. Elliott H. Lieb (Princeton University) |
| Abstract: | I will start with a quick review of the simple equation
derived in 1963 to calculate the ground state energy E of a dilute
Bose gas with 2-body repulsive interactions. It yielded the famous LHY
second order term for E. Beyond that it has been recently been shown
to agree remarkably well with Monte Carlo calculations in 3 dimensions
for ALL densities, revealing what might be previously unsuspected
changes at intermediate density. |
| Date: | Thu, 16.03.2023 |
| Time: | 16:15 |
| Duration: | 60 min |
| Location: | Erwin Schrödinger Institute, Boltzmanngasse 9, 1090 Wien, Boltzmann lecture hall |
| Contact: | secr@esi.ac.at |
| Thermal properties of quantum fields near spherically symmetric apparent horizon and Black Hole thermodynamics |
| Speaker: | Nicola Pinamonti (University of Genova) |
| Abstract: | In this talk we discuss the form of the correlation functions of a quantum scalar field near the apparent horizon of a spherically symmetric dynamical Black Hole. We show that if the quantum state is of Hadamard form, when a suitable scaling procedure towards the horizon is considered, a thermal spectrum along the integral lines of the Kodama vector fields can be detected. The temperature seen in this spectrum depends on the particular point of the apparent horizon towards which the scaling is performed thus allowing to analyze temperature changes along the apparent horizon itself. This evolution is compatible with the thermodynamic law of Black Hole dynamics. Furthermore, since this effect does not depend on the particular form of the chosen quantum state, it is shown to be universal.
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| Date: | Thu, 16.03.2023 |
| Time: | 17:00 |
| Duration: | 60 min |
| Location: | Freihaus, Seminar room 10th floor |
| Contact: | Romain Ruzziconi, Daniel Grumiller, Iva Lovrekovic |
| Quantum devices as a meeting point for thermodynamics and machine learning |
| Speaker: | Natalia Ares (Oxford University) |
| Abstract: | As we miniaturize devices to reach the quantum regime, the need arises to test the laws of thermodynamics in a new realm, in which fluctuations and quantum effects play a very important role. I will discuss how to explore the thermodynamics of semiconductor devices at nanometer scales, and I will explain how we measured the thermodynamic cost of recording the passage of time.
Electromechanical devices have great potential to build nanoscale motors. Fully suspended carbon nanotube devices allow us to control mechanical and electronic degrees of freedom with high accuracy. Using these devices we show that the transport of an electron can strongly couple to the nanotube motion. I will discuss how these experiments can be extended to study engines where the gas is one or two electrons and the piston is the movement of the nanotube.
These experiments and many others require increased levels o |
| Date: | Fri, 17.03.2023 |
| Time: | 10:00 |
| Duration: | 45 min |
| Location: | ATI Hörsaal/https://tuwien.zoom.us/j/93672218922?pwd=dEZNQ2liVzRNNURvNmVWVE5KUWRiQT09 |
| Contact: | Marcus Huber |
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