# Qubits and Spacetime Unit (Philipp Höhn)

The challenge of quantum gravity is to build a theory valid over all the scales down to the minuscule Planck scale, which explains how the known operational physics of general relativity and quantum (field) theory emerge from it. This deep challenge is the main impetus of the research efforts of the Qubits and Spacetime Unit, which reside at the interface of quantum gravity, quantum information and foundations.

The focus of our research does not lie on approach-specific problems, but on generic challenges, which many approaches to quantum gravity will have to face up to and which have implications and relevance also in other areas of physics. The idea is to develop concepts, tools and methodology, which will be useful for various approaches to quantum gravity and beyond, e.g., in many-body physics and quantum information and foundations.

### QI/QG Workshop 2022

#### Click here for more info.

#### Registration deadline: March 31st, 2022.

### Recent overview talks:

- Philipp Höhn, "Progress in relational quantum dynamics", Nov 5 2021,
*Theory of Relativity Seminar*, @*University of Warsaw*(video) - Philipp Höhn, "Progress in relational quantum dynamics", Sep 1 2021,
*Time in Quantum Theory*, Workshop @*ETH Zürich*(recording) - Philipp Höhn, "(Quantum) frame covariance: from foundations via gauge theories to gravity", June 16 2021,
*Quantizing Time*, Workshop @*Perimeter Institute*(video) - Philipp Höhn, "(Quantum) frame covariance in gauge systems and gravity", May 18 2021,
*Non-local Quantum Gravity Seminar, ENS Lyon*(video) - Philipp Höhn, "Perspective-neutral approach to quantum frame covariance", Nov 17 & 30 2020, two-part seminar, Quantum Information Theory Group of
*ETH Zürich*(video part 1, video part 2). - Philipp Höhn, "Problem of time, relational observables and quantum covariance", Oct 7 2020, inaugural talk of the new international seminar series initiative
*Quantum Gravity Across Approaches*(video). - Philipp Höhn, "Progress in relational quantum dynamics", Sep 15 2020,
*International LQG Seminar*(video).

### New articles:

- Anne-Catherine de la Hamette, Thomas D. Galley, Philipp A. Höhn, Leon Loveridge and Markus P. Müller, "Perspective-neutral approach to quantum frame covariance for general symmetry groups", arXiv:2110.13824
- Fabio Mele and Johannes Münch, "The Physical Relevance of the Fiducial Cell in Loop Quantum Cosmology", arXiv:2109.10663
- Sylvain Carrozza and Philipp A. Höhn, "Edge modes a reference frames and boundary actions from post-selection", arXiv:2109.06184
- Philipp A. Höhn, Marius Krumm, and Markus P. Müller, "Internal quantum reference frames for finite Abelian groups", arXiv:2107.07545
- Philipp A. Höhn, Maximilan P. E. Lock, Shadi Ali Ahmad, Alexander R. H. Smith, and Thomas D. Galley, "Quantum Relativity of Subsystems", arXiv:2103.01232
- Fabio Mele, Johannes Münch, and Stratos Pateloudis, "Quantum corrected polymer black hole thermodynamics: Mass relations and logarithmic entropy corrections", arXiv:2102.04788
- Josh Kirklin, "Islands and Uhlmann phase: Explicit recovery of classical information from evaporating black holes", arXiv:2011.07086
- Marius Krumm, Philipp A. Höhn, and Markus P. Müller, "Quantum reference frame transformations as symmetries and the paradox of the third particle",
*Quantum***5**, 530 (2021), arXiv:2011.01951 - Philipp A. Höhn, Alexander R. H. Smith, and Maximilian P. E. Lock, "Equivalence of approaches to relational quantum dynamics in relativistic settings",
*Front. Phys.***9**:587083 (2021), invited contribution to special issue "Qubits and Spacetime", arXiv:2007.00580

### Currently Taught Courses (more info):

- Covariant Physics and Black Hole Thermodynamics (by our postdocs Dr. Kirklin, Dr. Kotecha and Dr. Mele)