### Past Events

### Journal club seminar: Consistency of Quantum Theory

2018-10-19Discussion of the recent article in Nature by D. Frauchiger and R. Renner "Quantum theory cannot consistently describe the use of itself" by Henry Stoltenberg.

### QG group meeting: Fine-tuning and the Second Law in our de Sitter universe

2018-10-15**Quantum Gravity Group Meeting**

**Title:** Fine-tuning and the Second Law in our de Sitter universe

**Speaker**: Yasha Neiman

### Journal club seminar: Symmetries and Charges of General Relativity at Null Boundaries

2018-10-12Discussion on symmetries and charges in general relativity at null boundaries by Lin-Qing Chen.

### [Seminar] "Vacuum decay rate in the standard model and beyond" by Dr. Yutaro Shoji

2018-10-02Speaker: Dr. Yutaro Shoji from Nagoya University

Abstract:

The electroweak vacuum is not absolutely stable in the standard model and various models beyond the standard model. This is due to an appearance of another deeper vacuum, into which the electroweak vacuum can decay. The decay proceeds through quantum tunneling and the rate is expressed with an exponential suppression factor and a pre-factor. The suppression factor has been calculated in many papers, but a naive dimensional analysis has been usually adopted for the pre-factor.

We have pointed out that such an evaluation can suffer from large quantum corrections and it is important to calculate the pre-factor as well.

To calculate the pre-factor, we had problems in a gauge sector; its gauge invariance is not explicitly shown, and there appear zero modes, which we could not deal with.

We have solved these problems and made it possible to determine vacuum decay rates precisely.

As applications, we analyzed the decay rates in the standard model and its fermionic extensions. We also provide a public code, which can be used for models that exhibit classical scale invariance at a high energy scale.

### QG group meeting: Expansions of the Black Hole Solution in AdS(3)

2018-10-01**QG Group Meeting**

**Title:** Expansions of the Black Hole Solution in AdS(3)

**Speaker**: Nico Fischer, Research Intern, Quantum Gravity Unit (Neiman)

### Journal club seminar: Black hole memory effect

2018-09-27Discussion on Black Hole Memory Effect by Tomonori Ugajin.

### Journal club seminar: Wormholes

2018-09-21Discussion on Wormholes and Extra Dimensions by Vyacheslav Lysov.

### QG group meeting: Fluid/gravity correspondence

2018-09-10This is the weekly QG group meeting.

Speaker: Vyacheslav Lysov

Title: Fluid/Gravity Correspondence

### Journal club seminar: Geometry of Complexity

2018-09-07Discussion by Vyacheslav Lysov on Geometry of Complexity.

### QG group meeting: null hypersurface geometry

2018-09-03QG group meeting

Speaker: Yasha Neiman

Title: Introduction to the geometry of null hypersurfaces