# Covid precautions and regulations

We are committed to providing a safe environment for all participants of the conference. The event will be held in accordance with the local public health regulations valid at the time, which can be found here:

Information regarding the coronavirus (SARS-CoV-2)

In summary, as of August 2022, almost all Covid restrictions have been lifted. Masking however, at least with a medical mask, is still required in public transportation. Regarding the LMU premises the recommendation states: The wearing of masks is no longer compulsory. People are recommended to continue wearing surgical or FFP2 (N95) masks in cases where close contact with other individuals (without a minimum distance of 1.5 meters) is unavoidable (e.g. in face-to-face meetings, teamwork situations and longer periods of in-room presence).

In addition to that, and due to the rising case numbers and the absence of the summer slump in this year, we would kindly ask all participants to voluntarily do a self-test prior to their travel/arrival. For example, the following test station is in walking distance of the venue: Apotheke Maxvorstadt. Finally, in case you think you experience Covid symptoms, please stay at your accomondation and do not independently see a test station but ask the hotel to call a doctor who will then arrange a testing under safe conditions.

# Program (Last Update: August 2, 2022)

#### Schedule

Slot Monday Tuesday Wednesday Thursday Friday
09:00 - 10:00 Sheldon Goldstein Sergio Albeverio (postponed) Michael Kiessling Stefan Teufel (switched with Jean Bricmont) Herbert Spohn
10:00 - 10:30
Coffee Break
10:30 - 11:30 Jean Bricmont (switched with Stefan Teufel) Alessandro Pizzo Catalina Curceanu Lev Vaidman Tim Maudlin
11:30 - 12:30 Sören Petrat Antoine Tilloy Sandro Donadi Lea Bossman Closing, Short Addresses, Toasts, Buffet, Get-Together
12:30 - 15:00
Lunch break
15:00 - 16:00 Siddhant Das Rodolfo Figari Howard Wiseman Jürg Fröhlich
16:00 - 17:00 Fay Dowker Franz Merkl Short Talk Session Panel Discussion
17:00 - 17:30
Coffee break
17:30 - 18:30 Barry Loewer Nino Zanghì Niklas Boers Joel Lebowitz (Zoom)

#### Panel Discussion

• Panelists: Esfeld, Barbour, Kiessling, Loewer, Wiseman
• Chairs: Dustin Lazarovici, Paula Reichert-Schürmer

#### Short Talk Session

• Speakers: Serj Aristarhov, Yanxu Chen, Jose Luis Gaona Reyes, Matthias Lienert, Lorenzo Maccone, Aran O'Hare, Sahand Tokasi, Cornelia Vogel
• Chair: Ward Struyve

This session consists of a series of short talks, each of about 7 minutes, to different topics.

#### Book Table

There will be a book table by Angela Lahee and Springer where you can find books related to the topics of the conference. The book table will be located in room B 349 (third floor) next to where coffee is served.

#### Conference WiFi

Beside the eduroam WiFi network and the @BayernWLAN (which only requires a confirmation of the terms of use), we offer a local WiFi network which you can configure by following the intructions here: Wi-Fi-Guide for mwn-events.

This is the first conference of the Laws of Nature initiative. It will be taking place during August 8-12, 2022 at the Mathematical Institute of the LMU Munich in Munich. Following the goals of this initiative, it is aimed at bringing together senior and junior scientists and promote scientific exchange on fundamental questions in physics, philosophy, and mathematics.

This conference will in particular be held

and his profound legacy by means of bringing together many of the people, senior and junior, who in different ways played a major role in Detlef's life. In the spirit of Detlef's comprehensive approach to understanding the laws of nature, it will be an international and interdisciplinary conference covering physical, mathematical, and philosophical aspects in the foundations of physics.

The conference is organized by

# Registration

There is no registration fee but for the reasons of fire and potentially also Covid regulation we would require all participants to register with an email at:

conference2022@laws-of-nature.net

Please let us know your surname, first name, institution, and the duration of your stay at the conference.

For junior scientists who are willing to give a 5-10min presentation we will be offering limited funds for traveling. If you would like to apply for these funds, please indicate so and let us know title and abstract of a potential presentations.

# Travel and accommodation

The conference will take place at the

Mathematical Institute
Ludwig-Maximilians-Universität München
Theresienstrasse 39
80333 München

Arriving from the central train station: Take a "S-Bahn" in the direction of "Ostbahnhof". Exit at the next station "Karlsplatz/Stachus" and proceed to ground level following the signs to "Tram 27" in the direction of "Scheidplatz". Exit at the three stop which is called "Pinakotheken" which is located at the crossing of "Barerstrasse" and "Theresienstrasse". Find the institute directly in front of you when you exit the tram on the right.

Arriving from the airport: Take the S-Bahn S1 or S8 which are both leaving towards downtown. Exit at "Karlsplatz/Stachus" and then follow the above description.

We will have rooms reserved for speakers and panelists at: which are in walking distance to the institute.

Beside the above two hotels, there are many hotels in the vicinity of the conference and we kindly ask the participants to find a hotel and book early.

Important information about reimbursement of public and regional transport and "9 Euro Ticket"

The German government has introduced a cheap public and regional transport ticket, called 9-Euro-Ticket, for the months of June, July and August 2022. Please note that due to the implementation instructions of the State Ministry of Finance, for regional and public transportation only the 9-Euro-Ticket will be reimburseed.If a regular ticket is purchased for whose area of validity the 9-Euro ticket would also have sufficed, the costs can only be reimbursed up to a maximum of 9 Euros.

So please make sure, you buy a 9-Euro-Ticket whenever you are travelling by public transport, U-Bahn, S-Bahn, and regional trains!

The 9-Euro ticket can be purchased at any ticket machine. Detailed information on the ticket can be found on the website of Deutsche Bahn.

# Contact

We are looking forward to having you in Munich!

# Titles and Abstracts

Sheldon Goldstein: Bohmian Mechanics, Detlef, and OOEOW

Bohmian mechanics is the interpretation of quantum mechanics, or, better, version of quantum mechanics, that is most naturally suggested by the experimental facts that led to the rise of quantum mechanics in the first place. It is also the version of quantum mechanics that most naturally and most crisply accounts for the new experimental facts, such as quantum probabilities and quantum nonlocality, predicted by quantum mechanics.

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Stefan Teufel: Equilibration of Superposition Weights for Macroscopic Subspaces

To study the long-time behaviour of the unitary evolution of an isolated macroscopic quantum system, we assume (following von Neumann) that different macro states correspond to mutually orthogonal subspaces $$\mathcal{H}_\nu$$ (macro spaces) of the Hilbert space. Let $$P_\nu$$ denote the projection to $$\mathcal{H}_\nu$$. A pure state $$\psi_t$$ will generally be a superposition of contributions $$P_\nu\psi_t$$ from different $$\mathcal{H}_\nu$$'s. We ask how the superposition weights, i.e., the sizes $$\|P_\nu \psi_t\|^2$$ of these contributions, evolve for a typical initial state $$\psi_0$$ starting in some (possibly non-equilibrium) initial macro-state $$\mathcal{H}_\mu$$. We show that for large dimension $$d_\mu := \mathrm{dim}(\mathcal{H}_\mu)$$ the weights $$\|P_\nu \psi_t\|^2$$ evolve nearly deterministically for most $$\psi_0\in\mathcal{H}_\mu$$ (w.r.t. Haar measure) and approach certain time-independent values $$M_{\mu\nu}$$ for large $$t$$. Lower bounds on the values $$M_{\mu\nu}$$ can be obtained for certain random band matrices. This is joint work with Roderich Tumulka and Cornelia Vogel.

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Sören Petrat: The Binding Energy in the Weakly Interacting Bose Gas Beyond Bogoliubov Theory

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Siddhant Das: Arrival-time distributions and spin in quantum mechanics

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Fay Dowker: Recovering General Relativity from a Planck scale discrete theory of quantum gravity

I will present an argument that if a theory of quantum gravity is physically discrete at the Planck scale and the theory recovers General Relativity as an approximation, then, at the current stage of our knowledge, causal sets must arise within the theory, even if they are not its basis. We show in particular that an apparent alternative to causal sets, viz. a certain sort of discrete Lorentzian simplicial complex, cannot recover General Relativistic spacetimes in the appropriately unique way. For it cannot discriminate between Minkowski spacetime and a spacetime with a certain sort of gravitational wave burst. This talk is based on joint work with Jeremy Butterfield, available at https://arxiv.org/abs/2106.01297.

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Barry Loewer: 🚧

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Sergio Albeverio (postponed -- will take place on Zoom somewhat later in the year): 🚧

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Alessandro Pizzo: Stability of gapped quantum systems under small perturbations

I will consider families of quantum lattice systems that have attracted much interest amongst people studying topological phases of matter. Their Hamiltonians are perturbations, by interactions of short range, of a Hamiltonian consisting of strictly local terms and with a (strictly positive) energy gap above its ground-state energy. I will review the main ideas of a novel method based on local Lie-Schwinger conjugations of the Hamiltonians associated with connected subsets of the lattice. By this method fermions and bosons are treated on the same footing, and our technique does not face a large field problem, even though bosons are involved.

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Antoine Tilloy: 🚧

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Rodolfo Figari: Revisiting quantum mechanical zero range potentials and interactions

A careful look to the entire family of operators known as many center quantum point interaction Hamiltonians indicates that they do not show any singular or trivial behaviour when the positions of two or more scattering centres tend to coincide. In this sense, they appear to be a “by default" regularisation of the point interaction Hamiltonians defined via identical boundary conditions at each point of the scattering centre array. We will summarise some properties of this latter sub-family of Hamiltonians and we will try to clarify the renormalisation mechanism which makes them regular and physically relevant. We also investigate the reproducibility of the same regularisation mechanism in systems of many quantum particles interacting via zero range forces.

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Franz Merkl: Electric four-current in external field QED

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Nino Zanghì: Particles, Fields & Beyond

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Michael Kiessling: The classical electromagnetic radiation-reaction problem

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Catalina Curceanu: Blues in the Cosmic Silence: testing Quantum Mechanics Underground -- Strike another match, go start anew

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Sandro Donadi: Collapse dynamics are diffusive

Testing the limits of validity of the superposition principle is of crucial importance in the foundations of quantum mechanics and the development of quantum technologies. A way to quantify possible breakdowns of the superposition principle is given by collapse models. These models modify quantum mechanics by introducing a nonlinear interaction with a classical noise that induces collapse in space. The natural way of testing collapse models is through interferometric experiments of systems with large masses, which is challenging. For this reason, non-interferometric experiments were considered. These experiments exploit the fact that the noise responsible for the collapse induces a diffusion in momentum, in principle detectable even in localized systems by performing high precision position measurements. We first give a summary of the bounds on collapse models from non-interferometric experiments. Then we show how the diffusion in momentum is not just a property of collapse models but it is a universal feature of any dynamics inducing collapse in space. This implies that non-interferometric experiments test the quantum superposition principle in a stronger sense than one might suppose.

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Howard Wiseman: Beyond Bell: Experimental Metaphysics in Collaboration with a Quantum Computer

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Niklas Boers: Critical Transitions in the Earth System

In response to anthropogenic release of greenhouse gases, the Earth is warming at unprecedented rates. It has been suggested that several components of the Earth’s climate system may respond with abrupt transitions between alternative stable states in response to gradual changes in forcing. Based on the theory of stochastically forced dynamical systems and their bifurcations, a methodology is presented to measure changes in the stability of a given equilibrium state from observational time series. The method is applied to investigate if and how the stability of the Greenland Ice Sheets, a circulation system in the Atlantic Ocean, and the Amazon rainforest, has varied in the course of the last century.

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Jean Bricmont: Why Bohm and only Bohm?

It is often claimed that there are three "realist" versions of quantum mechanics: the de Broglie-Bohm theory or Bohmian mechanics, the spontaneous collapse theories and the many worlds interpretation. We will explain why the two latter proposals suffer from serious defects coming from their ontology (or lack thereof) and that the many worlds interpretation is unable to account for the statistics encoded in the Born rule. The de Broglie-Bohm theory, on the other hand, has no problem of ontology and accounts naturally for the Born rule.

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Lev Vaidman: Can Bohmian mechanics be the leading interpretation?

I believe this was the main question of Detlef Durr research. My views in favor and against Bohmian interpretation will be presented. The question of the possibility of observational differences between Bohmian mechanics and other interpretations (including experiments with unlimited technological power) will be analyzed. The light "surrealistic Bohmian trajectories" shed on this question will be discussed.

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Lea Bossman: Edgeworth expansion for the weakly interacting Bose gas

We consider the ground state of a system of N weakly interacting bosons. We derive an Edgeworth expansion for the fluctuations of bounded one-body operators around the condensate, which yields corrections to a central limit theorem to any order in $$1/N$$. This is joint work with Sören Petrat.

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Jürg Fröhlich: The Classical Periphery of Quantum Mechanics - The Example of Particle Tracks in Detectors

In this talk I consider regimes of Quantum Mechanics that can be described in classical terms. Such regimes constitute what I call the "Classical Periphery/Skin of Quantum Mechanics." I won’t develop the general theory, but illustrate it in a study of tracks traced out by quantum-mechanical particles propagating in detectors. These tracks are close to classical particle trajectories. I will begin the talk with some general comments on the notion of "events" in Quantum Mechanics and their role in understanding "state reduction", as manifested in measurements and observations. My discussion is cast in what I have dubbed "ETH-Approach to QM", which I regard as a cornerstone of Quantum Geometry.

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Joel Lebowitz (Zoom): Boltzmann's Entropy for Macroscopic Systems: Classical and Quantum

Boltzmann’s entropy is defined for individual macroscopic systems in a specified macrostate; equillibirum or not. In the latter case it satisfies the second law of thermodynamics which characterizes the time evolution of a typical isolated macroscopic system in a non-equilibrium macrostate. The time asymmetry of this observed evolution can be understood as arising from: a) the great disparity betreen microscopic and macroscopic sizes, b) initial conditions, and c) what we observe are typical behaviors — not all imaginable ones. While Boltzmann considered classical microscopic laws his conclusions also hold, with some modifications, for quantum systems.

Join on Zoom here.

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Herbert Spohn: Microscopic derivation of the Boltzmann equation - Lanford’s theorem and recent advances

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Tim Maudlin: On the Emergence of Relativistic Structure from Discrete Space-Time with a Global Foliation

The empirical success of Special and General Relativity, and of theories that incorporate Relativistic symmetries, argues that the Relativistic account of space-time structure must approximate the truth. But on the other hand, the confirmed violations of Bell’s Inequality for experiments done at space-like separation equally appears to argue for some global foliation of space-time that does not appear in the Relativistic theory.

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