Stat.Phys. seminars coming up

[Cond.Matt. & Stat.Mech.Section]

INFORMAL SEMINAR on    Statistical Physics
 


Luigi Stasi Seminar Room -  Leonardo Building    (first floor)

 

Thursday, 1 July -     11:30 a.m.

 

Subir K. DAS    ( Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore)

 

"Nucleation and growth in binary mixtures: Revisiting symmetric cases"

 
Abstract

 

In this lecture, I will describe kinetics of phase separation in symmetric binary mixtures.  Consequence of curvature dependent interfacial tension will be discussed in the context of early time dynamics.

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JOINT ICTP/SISSA STATISTICAL PHYSICS SEMINAR
 

Tuesday, 6 July   -   11:30 hrs.

 

Luigi Stasi Seminar Room,  ICTP Leonardo Building - 1st floor

 

Alexander MOZEIKA       (Aston University, Birmingham)


 

"Reliable computation by noisy Boolean formulas -    A statistical physics approach"
 

Abstract

 

Noise is inherent in most forms of computing and its impact is more dramatic as the computing circuits become more complex and of large scale. Classical computing circuits suffer from thermal noise and production errors, quantum computers suffer from decoherence, whilst an understanding of noisy processes, inherent in neural networks and biological systems, remains poorly understood.

The first model of noisy computation was proposed by von Neumann in 1956 who used circuits/formulas composed of noisy Boolean gates to gain insight into the robustness of biological neuronal networks. A noisy circuit cannot perform any given computation in a deterministic manner: for any circuit-input there is a non-vanishing probability that the circuit will produce the wrong output. Von Neumann showed that reliable computation (probability of error < 1/2) is possible for small gate-noise values and specific gates, and demonstrated how reliability can be improved using noisy gates only. In a more recent analysis Pippenger demonstrated that formulas only compute reliably up to a certain gate-noise threshold and that reliable computation with noisy gates requires strictly greater formula-depth.  A number of papers have followed which improved and extended these results. The latter mainly rely on specific circuit constructions and methods that correspond to the worst case analysis.

In this talk we show how random Boolean formulas can be mapped onto a physical framework and employ methods of statistical physics, developed specifically to analyze the typical behavior of random disordered systems, to gain insight into the behavior of noisy Boolean random formulas. We show that the typical-case macroscopic behavior observed corresponds straightforwardly to the bounds obtained in the theoretical computer science literature. Being very general, the framework is extended to consider further properties of random Boolean formulas for different gates and their dependence on the gate-noise level and formula depth.

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Ms. M. Poropat
Secretary
Condensed Matter & Statistical Physics Section
The Abdus Salam International
  Centre for Theoretical Physics
Strada Costiera 11
34151 Trieste
Italy

Telephone: +39-040-2240540
Telefax: +39-040-2240354 or 224163


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