Seminars

Title: Reaching the fundamental limits of device-independent quantum information processing
 
Abstract:  In this talk I will discuss recent results on reaching fundamental limits in device-independent quantum information processing protocols.

While it is known that Bell non-locality is necessary for device-independent quantum key distribution (DIQKD), we recently showed that it is not sufficient in most protocols [1]. This raises the question whether some minimal amount of non-locality is necessary for DIQKD. I will show that this is not the case--in fact, correlations arbitrarily close to the set of local correlations allow for unbounded device-independent key rates [2].

Then, I will move on to randomness generation, and show that the maximal theoretically possible 2*log(d) bits of device-independent randomness can be extracted from a locally d-dimensional maximally entangled state in every dimension d, using a new relaxed version of the famous family of symmetric informationally complete (SIC) POVMs [3].

In the talk, I will not assume any prior knowledge of Bell non-locality or device-independence, only the basics of finite-dimensional quantum theory.

[1] M Farkas, M Balanzó-Juandó, K Łukanowski, J Kołodyński, A Acín, Physical Review Letters 127 (5), 050503 (2021)
[2] M Farkas, Physical Review Letters 132 (21), 210803 (2024)
[3] M Farkas, J Volčič, SAL Storgaard, R Chen, L Mančinska arXiv:2409.18916