# IPhT/LPTMS Days: Quantum Day

**The IPhT/LPTMS days: Quantum Day ****at the « Petit amphi » at Pascal Building (9h15 – 12h30)**

### 9h15 : Opening speech by the directors

### 9h30 : Leonardo Mazza (LPTMS)

*Fractional spin and fractional statistics of quantum Hall quasiparticles from density profiles*

We present a study of the quasiparticle excitations that appear in the fractional quantum Hall effect. Focusing on several examples, including the Laughlin state, the Halperin 221 state and the Moore-Read state, we show that the density profile of the liquid hosting them contains information about their fractional spin and statistics. In particular, by studying the second moment of the so-called depletion density, it is possible to compute the fractional spin of the quasiparticles, and using the spin-statistics theorem to compute their fractional statistics. The possibility of accessing these properties without using interferometric schemes may open the way to novel experiments using for instance ultra-cold gases or fluids of light.

### 10h : Cristina Bena (IPHT)

*Majorana and other boundary modes from impurity states via T-matrix*

We provide a new and exact formalism to describe the formation of end, edge or surface states through the evolution of impurity-induced states. We propose a general algorithm that consists of finding the impurity states via the T-matrix formalism and showing that they evolve into boundary modes when the impurity potential goes to infinity. We apply this technique to obtain Majorana states, topological insulator edges states and graphene edges states. We also show that this approach provides us with a new direct and non-numerical technique to obtain the surface Green’s functions for three-dimensional systems and we apply it to Weyl semimetals.

### 10h30 : Coffee Break

### 11h : Dmitry Petrov (LPTMS)

*Beyond-mean-field effects in quantum gases*

### 11h30 : Jean-Daniel Bancal (IPHT)

*Device-independent quantum key distribution*

### 12h : Mikhail Zvonarev (LPTMS)

**Mobile impurity in one dimension**

### 12h30 : Lunch buffet

**Date/Time : ** 14/04/2022 - *9:30 - 12:30*

**Location : ** Petit amphi, bâtiment Pascal n° 530

#### Upcoming seminars

- Journées des laboratoires FFJ - 15 Sep 2022 - 00:00
- Séminaire du LPTMS : Alberto Nardin (UniTn) - 20 Sep 2022 - 11:00
- Soutenance de thèse Félix Benoist - 28 Sep 2022 - 14:00
- Physics-Biology interface seminar: Anne-Marie Haghiri - 30 Sep 2022 - 11:00
- Soutenance de thèse Pierre Mergny - 12 Oct 2022 - 14:00
- Soutenance de thèse : Lorenzo Gotta (LPTMS) - 8 Nov 2022 - 00:00
- Physics-Biology interface seminar: Léa Chazot-Franguiadakis - 18 Nov 2022 - 11:00