ELFT HÍRADÓ

[Janos Asboth <asboth AT phy.bme.hu>]

Meghívó

BME Elméleti Fizika Szeminárium,

október 2. péntek 10h15,
online a Microsoft Teamsben,

Grabarits András (BME TTK, Elméleti Fizika Tanszék):

Theory of quantum work in metallic grains

We generalize Anderson’s orthogonality determinant formula to describe the
statistics of work performed on generic disordered, noninteracting
fermionic nanograins during quantum quenches. The energy absorbed increases
linearly with time, while its variance exhibits a superdiffusive behavior
due to Pauli’s exclusion principle. The probability of adiabatic evolution
decays as a stretched exponential. In slowly driven systems, work
statistics exhibit universal features and can be understood in terms of
fermion diffusion in energy space, generated by Landau-Zener transitions.
This diffusion is very well captured by a Markovian symmetrical exclusion
process, with the diffusion constant identified as the energy absorption
rate. The energy absorption rate shows an anomalous frequency dependence at
small energies, reflecting the symmetry class of the underlying
Hamiltonian. Furthermore, in order to extract the analytical properties of
the statistical behaviour of the injected work we introduce a simple mean
field theory incorporating only the Pauli exclusion principle, the
conservation of the total number of particles and the diffusive character
of the occupation numbers. Our predictions can be experimentally verified
by calorimetric measurements performed on nanoscale circuits.

Related Publication: I Lovas, A Grabarits, M Kormos, G Zaránd, Phys. Rev.
Research 2, 023224 (2020)

Minden érdeklődőt szeretettel várunk.

Asbóth János
szemináriumi koordinátor