ELFT HÍRADÓ

[Janos Asboth <asboth.janos AT ttk.bme.hu>]

Meghívó

BME Elméleti Fizika Szeminárium,

máj. 19. péntek 10h15,

1111 Budapest, Budafoki út 8., BME F III. magasföldszint 01.,
Elméleti Fizika Tanszék szemináriumi szoba

Juhász Róbert (Wigner FK SZFI):
Exact bounds on the energy gap of transverse-field Ising chains by mapping
to random walks

Based on a relationship with continuous-time random walks [1], we derive
[2] exact lower and upper bounds on the lowest energy gap of open
transverse-field Ising chains, which are explicit in the parameters and are
generally valid for arbitrary sets of possibly random couplings and fields.
In the homogeneous chain and in the random chain with uncorrelated
parameters, both the lower and upper bounds show the same finite-size
scaling in the ferromagnetic phase and at the critical point, demonstrating
the ability of these bounds to infer the correct finite-size scaling of the
critical gap. Applying the bounds to random transverse-field Ising chains
with coupling-field correlations, a model which is relevant for adiabatic
quantum computing, the finite-size scaling of the gap is shown to be
related to that of sums of independent random variables. We determine the
critical dynamical exponent of the model and reveal the existence of
logarithmic corrections at special points.

[1]: F Iglói, L Turban, and H Rieger, Phys. Rev. E 59, 1465 (1999)
[2]: R Juhász, Phys. Rev. B 106, 064204 (2022)

Minden érdeklődőt szeretettel várunk.
Asbóth János,
 szemináriumi koordinátor