Hi all,
Tomorrow Lorenzo Laneve will tell us about his semester project with Lídia,
entitled "Impossibility of composable Oblivious Transfer in relativistic
quantum cryptography". See below for the abstract. We start at 2pm on zoom:
https://ethz.zoom.us/j/362994444.
Best,
Joe
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https://arxiv.org/abs/2106.11200
Abstract: We study the cryptographic primitive Oblivious Transfer; a
composable construction of this resource would allow arbitrary multi-party
computation to be carried out in a secure way, i.e. to compute functions in
a distributed way while keeping inputs from different parties private.
First we review a framework that allows us to analyze composability of
classical and quantum cryptographic protocols in special relativity:
Abstract Cryptography implemented with Causal Boxes. We then (1) explore
and formalize different versions of oblivious transfer found in the
literature, (2) prove that their equivalence holds also in relativistic
quantum settings, (3) show that it is impossible to composably construct
any of these versions of oblivious transfer from only classical or quantum
communication among distrusting agents in relativistic settings, (4) prove
that the impossibility also extends to multi-party computation, and (5)
provide a mutual construction between oblivious transfer and bit commitment.
Hi all,
Tomorrow we will hear from Davide Materia on his master's thesis with Ivano
Tavernelli at IBM, entitled "DFT functionals trained with Quantum
Computers". See below for the abstract. We start at 2pm on zoom:
https://ethz.zoom.us/j/362994444.
Best,
Joe
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Abstract: In this thesis, we developed different methods for the training
and the optimization of a Density Functional Theory (DFT) exchange and
correlation functionals, vxc, which relies on the minimization of the
electronic density difference obtained by subtracting the approximated DFT
density with a reference one evaluated on a quantum computer. The
determination of accurate and universal DFT vxc functional represents an
unsolved problem in computational chemistry and despite many attempts
(based on theoretical as well as heuristic approaches) a general solution
that is applicable in all physical contexts is still lacking. The new
generation of DFT functionals are build combining different energy
contributions and energy corrections (such as exchange, correlation but
also van der Waals energy terms with different short and long range
behaviors) weighted by a number of parameters that are usually fitted to
minimize the errors on a set of properties (mainly relative energies) in a
training set of molecules and solid state systems.
In this work, motivated by the central role of the density in the
Hohenberg-Kohn theorem, we investigate the possibility to use directly the
electronic density of molecular systems to optimize the DFT functionals,
hoping for a greater universality of the new functional resulting from this
optimization.