Top-level heading

Absence of small-world effects at the quantum level and stability of the quantum critical point

Data e ora inizio evento
Data e ora fine evento
Sede

Dipartimento di Matematica Guido Castelnuovo, Università Sapienza Roma

Aula
Aula G
Speaker ed affiliazione
Massimo Ostilli
The small-world effect is a universal feature used to explain many different phenomena like percolation, diffusion, and consensus. Starting from any regular lattice of N sites, the small-world effect can be attained by rewiring randomly O(N ) links or by superimposing O(N ) new links onto the system. In a classical system this procedure is known to change radically its critical point and behavior, the new system being always effectively mean-field. Here, we prove that at the quantum level the above scenario does not apply: when an O(N ) number of new couplings are randomly superimposed onto a quantum Ising chain, its quantum critical point and behavior both remain unchanged. In other words, at zero temperature quantum fluctuations destroy any small-world effect. The derivation is obtained by combining the quantum-classical mapping with topological arguments.
Contatti/Organizzatori
carlo.presilla@uniroma1.it