arXiv subjects

José Ramón Martínez Saavedra

Publications and source records attributed to José Ramón Martínez Saavedra.

3 recordsLinked to original sources

arXiv2025

Integration of quantum random number generators with post-quantum cryptography algorithms

As quantum technologies advance, the security of popular cryptographic protocols becomes more threatened by the capabilities of Cryptographically Relevant Quantum Computers (CRQCs). In this scenario, Post-Quantum Cryptography (PQC) has become a potential solution to prolong the life of existing Public Key Infrastructure (PKI) systems. However, PQC protocols depend on high-quality randomness for key generation and encapsulation procedures, with the quality of the entropy source potentially having a profound impact on the security of the overall system. In this work, we demonstrate a proof-of-concept enabling the incorporation of Quantum Random Number Generation (QRNG) devices within communication networks using PQC-based Transport Layer Security (TLS).Using open-source cryptographic libraries and commercial QRNG hardware, we demonstrate their use as entropy sources via an Entropy-as-a-Service (EaaS) model. We highlight two particular use cases: a fully virtualized private PKI network and a connection to an external PQC-enabled server. Experimental results show that EaaS QRNG enables real-time entropy monitoring and quality assessment in cryptographic management systems, with negligible impact on TLS handshake time.

quant-ph↗

arXiv2024

Population annealing with topological defect driven nonlocal updates for spin systems with quenched disorder

Population Annealing, one of the currently state-of-the-art algorithms for solving spin-glass systems, sometimes finds hard disorder instances for which its equilibration quality at each temperature step is severely damaged. In such cases one can therefore not be sure about having reached the true ground state without vastly increasing the computational resources. In this work we seek to overcome this problem by proposing a quantum-inspired modification of Population Annealing. Here we focus on three-dimensional random plaquette gauge model which ground state energy problem seems to be much harder to solve than standard spin-glass Edwards-Anderson model. In analogy to the Toric Code, by allowing single bond flips we let the system explore non-physical states, effectively expanding the configurational space by the introduction of topological defects that are then annealed through an additional field parameter. The dynamics of these defects allow for the effective realization of non-local cluster moves, potentially easing the equilibration process. We study the performance of this new method in three-dimensional random plaquette gauge model lattices of various sizes and compare it against Population Annealing. With that we conclude that the newly introduced non-local moves are able to improve the equilibration of the lattices, in some cases being superior to a normal Population Annealing algorithm with a sixteen times higher computational resource investment.

cond-mat.dis-nn↗

arXiv2019

Imaging the Renner-Teller effect using laser-induced electron diffraction

Structural information on electronically excited neutral molecules can be indirectly retrieved, largely through pump-probe and rotational spectroscopy measurements with the aid of calculations. Here, we demonstrate the direct structural retrieval of neutral carbonyl disulfide (CS$_2$) in the B$^1$B$_2$ excited electronic state using laser-induced electron diffraction (LIED). We unambiguously identify the ultrafast symmetric stretching and bending of the field-dressed neutral CS$_2$ molecule with combined picometer and attosecond resolution using intrapulse pump-probe excitation and measurement. We invoke the Renner-Teller effect to populate the B$^1$B$_2$ excited state in neutral CS$_2$, leading to bending and stretching of the molecule. Our results demonstrate the sensitivity of LIED in retrieving the geometric structure of CS$_2$, which is known to appear as a two-center scatterer.

physics.chem-ph↗