# 260078 SE Device-independent Physics (2019S)

Continuous assessment of course work

## Labels

## Registration/Deregistration

- Registration is open from
**Mo 04.02.2019 08:00**to**Mo 25.02.2019 07:00** - Deregistration possible until
**Th 21.03.2019 23:59**

## Details

max. 15 participants

Language: English

### Lecturers

### Classes

Vorbesprechung: 07.03.19, 14:00 Uhr, IQOQI SR Raum

Do 14:00-15:30, IQOQI SR Raum## Information

### Aims, contents and method of the course

When physicists do not trust the calibration of the devices composing an experimental setup, they can opt to model the whole experiment via a black box, where one inputs a symbol (the type of experiment) and returns an output (the outcome of the experiment). Remarkably, in some situations, the mere correlations between different laboratories (or boxes) allow one to learn something meaningful about the contents of each box. E.g.: assuming that the system inside the box is quantum, correlations between different boxes are enough to lower bound the Hilbert space dimension of the underlying quantum state. Morever, since different physical theories predict different possible correlations between distant observers, some of such “device-independent” experiments can reveal the nature of the system within the black box. In this course we will learn what makes correlations physical (classical, quantum or otherwise) and how different assumptions on the underlying experimental setups translate at the level of correlations.

### Assessment and permitted materials

oral presentations

### Minimum requirements and assessment criteria

Linear algebra and quantum physics.

### Examination topics

1. Classical boxesa) Bell’s theorem. Characterization of Bell nonlocality.b) Hidden variable models with secret communication.c) Boxes in large symmetric systems2. Quantum boxesa) The limits of quantum correlations: Tsirelson’s bound. XOR games.b) Finite dimensions are not enough: non-closure of the set of quantum boxes.c) Characterization of quantum boxesd) Lower bounding the Hilbert space dimension with correlationse) Self-testing: quantum systems which verify themselves3. Classifying general physical theories by their correlationsa) Physical sets of correlations. Closure under wirings: definition, properties, examples. Monotones under wirings.b) Do we expect correlations to be very different from quantum? Five device-independent physical principles to constrain physical correlations: no-trivial communication complexity, no-advantage for nonlocal computation, information causality, macroscopic locality and local orthogonality.c) The limitations of black box physics: the almost-quantum set of correlations4. Boxes and timea) Prepare-and-measure scenariosb) Finite-state automata

### Reading list

Nicolas Brunner, Daniel Cavalcanti, Stefano Pironio, Valerio Scarani, Stephanie Wehner, Bell nonlocality, Rev. Mod. Phys. 86, 419 (2014).Nicolas Brunner, Stefano Pironio, Antonio Acin, Nicolas Gisin, Andre Allan Methot, Valerio Scarani, Testing the Hilbert space dimension, Phys. Rev. Lett. 100, 210503 (2008).Ben Lang, Tamas Vertesi, Miguel Navascues, Closed sets of correlations: answers from the zoo, Journal of Physics A 47, 424029 (2014).Miguel Navascues, Tamas Vertesi, Bounding the set of finite dimensional quantum correlations, Phys. Rev. Lett. 115, 020501 (2015).Jean-Daniel Bancal, Stefano Pironio, Antonio Acin, Yeong-Cherng Liang, Valerio Scarani, Nicolas Gisin, Quantum nonlocality based on finite-speed causal influences leads to superluminal signaling, Nature Physics 8, 867 (2012).Jordi Tura, Gemma De las Cuevas, Remigiusz Augusiak, Maciej Lewenstein, Antonio Acín, J. Ignacio Cirac, Energy as a detector of nonlocality of many-body spin systems, Phys. Rev. X 7, 021005 (2017).Miguel Navascués, Yelena Guryanova, Matty J. Hoban, Antonio Acín, Almost quantum correlations, Nature Communications 6, 6288 (2015).G. Brassard, H. Buhrman, N. Linden, A. A. Methot, A. Tapp and F. Unger, F., Limit on Nonlocality in Any World in Which Communication Complexity Is Not Trivial, Phys. Rev.

Lett., 96 250401, (2006).N. Linden, S. Popescu, A. J. Short, and A. Winter, Quantum Nonlocality and Beyond: Limits from Nonlocal Computation, Phys. Rev. Lett. 99, 180502 (2007).M. Pawlowski, T. Paterek, D. Kaszlikowski, V. Scarani, A. Winter, and M. Zukowski, Information Causality as a physical principle, Nature 461, 1101 (2009).M. Navascués and H. Wunderlich, A glance beyond the quantum model, Proc. Royal Soc. A 466:881-890 (2009).T. Fritz, A. B. Sainz, R. Augusiak, J. B. Brask, R. Chaves, A. Leverrier and A. Acín, Local orthogonality as a multipartite principle for quantum correlations, Nature Communications 4, 2263 (2013).

Lett., 96 250401, (2006).N. Linden, S. Popescu, A. J. Short, and A. Winter, Quantum Nonlocality and Beyond: Limits from Nonlocal Computation, Phys. Rev. Lett. 99, 180502 (2007).M. Pawlowski, T. Paterek, D. Kaszlikowski, V. Scarani, A. Winter, and M. Zukowski, Information Causality as a physical principle, Nature 461, 1101 (2009).M. Navascués and H. Wunderlich, A glance beyond the quantum model, Proc. Royal Soc. A 466:881-890 (2009).T. Fritz, A. B. Sainz, R. Augusiak, J. B. Brask, R. Chaves, A. Leverrier and A. Acín, Local orthogonality as a multipartite principle for quantum correlations, Nature Communications 4, 2263 (2013).

## Association in the course directory

MaG 18, M-VAF A 2, M-VAF B, MaV 5

*Last modified: Tu 14.05.2019 13:28*