arXiv subjects

J. Sakellariou

Publications and source records attributed to J. Sakellariou.

2 recordsLinked to original sources

arXiv2026

Precision Hamiltonian Encoding in Full-Aperture Spatial Photonic Ising Machines

Spatial photonic Ising machines (SPIMs) offer compact, room-temperature hardware with inherently parallel, energy-efficient, single-shot optical evaluation of the Ising Hamiltonian. However, accurate operation has been fundamentally limited by optical aberrations and non-uniform illumination, which corrupt phase-based spin encoding and distort coupling representation, forcing operation to a restricted spatial light modulator (SLM) region. Here we introduce a high-precision full-aperture calibration scheme that overcomes these constraints. By implementing wavefront retrieval and correction with $<λ/40$ accuracy, we restore faithful phase encoding across the entire SLM area. Furthermore, we introduce an interaction-normalization method, which compensates for amplitude curvature and enables uniform coupling representation. Together, these advances establish a full-aperture SPIM architecture whose faithful Hamiltonian encoding is a prerequisite for photonic Ising computation.

physics.optics↗

arXiv2011

Exact mean field inference in asymmetric kinetic Ising systems

We develop an elementary mean field approach for fully asymmetric kinetic Ising models, which can be applied to a single instance of the problem. In the case of the asymmetric SK model this method gives the exact values of the local magnetizations and the exact relation between equal-time and time-delayed correlations. It can also be used to solve efficiently the inverse problem, i.e. determine the couplings and local fields from a set of patterns, also in cases where the fields and couplings are time-dependent. This approach generalizes some recent attempts to solve this dynamical inference problem, which were valid in the limit of weak coupling. It provides the exact solution to the problem also in strongly coupled problems. This mean field inference can also be used as an efficient approximate method to infer the couplings and fields in problems which are not infinite range, for instance in diluted asymmetric spin glasses.

cond-mat.dis-nn↗