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P. S. Karavelas

Publications and source records attributed to P. S. Karavelas.

2 recordsLinked to original sources

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↗

A magnetic falling-sphere viscometer

We present a falling-sphere viscometer with a magnetized sphere and fluxgate magnetometers continuously measuring the magnetic field produced at the sensor positions by the falling sphere. With a fluid volume of 15 ml and within a few seconds, we directly measure dynamical viscosities in a range between 200 cP and 3000 cP with a precision of 3\%.

physics.app-ph↗