Erio Tosatti

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Probing the lowest energy configuration of a complex system by quantum annealing was recently found to be more effective than its classical, thermal counterpart. By comparing classical and quantum Monte Carlo annealing protocols on the two-dimensional random Ising model (a prototype spin glass), we confirm the superiority of quantum annealing relative to(More)
L.Pietronero, E. Tosatti, V. Tosatti and A. Vespignani 1Dipartimento di Fisica and Unitá INFM dell’Universitá di Roma “La Sapienza”, P.le A. Moro 2, I-00185 Roma, Italy 2 SISSA/ISAS, Via Beirut 2-4, 34014 Trieste, Italy 3 The Abdus Salam International Centre for Theoretical Physics (ICTP), P.O.Box 586, 34100 Trieste, Italy Suppose you look at today’s stock(More)
Surface roughness has a huge impact on many important phenomena. The most important property of rough surfaces is the surface roughness power spectrum C(q). We present surface roughness power spectra of many surfaces of practical importance, obtained from the surface height profile measured using optical methods and the atomic force microscope. We show how(More)
The phase diagrams of water and ammonia were determined by constant pressure ab initio molecular dynamic simulations at pressures (30 to 300 gigapascal) and temperatures (300 to 7000 kelvin) of relevance for the middle ice layers of the giant planets Neptune and Uranus. Along the planetary isentrope water and ammonia behave as fully dissociated ionic,(More)
We propose a path-integral Monte Carlo quantum annealing scheme for the symmetric traveling-salesman problem, based on a highly constrained Ising-like representation, and we compare its performance against standard thermal simulated annealing. The Monte Carlo moves implemented are standard, and consist in restructuring a tour by exchanging two links(More)
of dissociated molecules (and thus of the protonic carriers) increase exponentially across the molecular-ionic cross-over. In the ionic regime all the protons contribute equally to the conductivity, and a further increase in pressure increases the proton mobility without changing the number of carriers. Moving deeper into the planet, the ice core boundary(More)
Sliding friction between crystal lattices and the physics of cold ion traps are so far non-overlapping fields. Two sliding lattices may either stick and show static friction or slip with dynamic friction; cold ions are known to form static chains, helices or clusters, depending on the trapping conditions. Here we show, based on simulations, that much could(More)
Understanding the structural transformations of solid CO(2) from a molecular solid characterized by weak intermolecular bonding to a 3-dimensional network solid at high pressure has challenged researchers for the past decade. We employ the recently developed metadynamics method combined with ab initio calculations to provide fundamental insight into recent(More)