arXiv subjects

F. P. M. Méndez-Córdoba

Publications and source records attributed to F. P. M. Méndez-Córdoba.

3 recordsLinked to original sources

arXiv2026

Magnetization of electronic ground states in frustrated superstable graphs

Geometric frustration lies at the heart of many unconventional quantum phases in strongly interacting electron systems. Here, we analytically determine the ground state magnetization of the half-filled Hubbard model on frustrated geometries where superstable states -- eigenstates which are robust against frustration -- are manifest. Our results apply to a broad class of lattices, including those where altermagnetic and superconducting states are known to emerge. Furthermore, they provide evidence for phase transitions involving a geometric rearrangement of magnetic correlations in the thermodynamic limit.

cond-mat.str-el↗

arXiv2023

From edge to bulk: Cavity induced displacement of topological non-local qubits

We investigate the ability of selective cavity coupling to a topological chain for tailoring the connectivity of Majorana fermions. We show how topological qubits (TQs), associated with non-local Majorana fermion pairing, can be moved from the edge to the bulk of a topological chain through selective access to light-matter interaction with specific physical sites. In particular, we present a comprehensive DMRG study of ground-state features in different chain-cavity coupling geometries and validate analytical insights in the strong coupling regime. This new kind of Majorana fermion correlation generation process comes with new cavity photon features. Moreover, by considering the time evolution after a sudden quench of the cavity-matter coupling strength, we show that the development of high non-trivial matter (Majorana) correlations leaves off measurable non-classical photon imprints in the cavity. New ways to dynamically generate TQ nonlocal correlations in topological chains of arbitrary length are thus provided, opening alternative routes to controllable long-range entanglement in hybrid photonic solid-state systems.

cond-mat.mes-hall↗

arXiv2020

Rényi Entropy Singularities as Signatures of Topological Criticality in Coupled Photon-Fermion Systems

We show that the topological phase transition for a Kitaev chain embedded in a cavity can be identified by measuring experimentally accessible photon observables such as the Fano factor and the cavity quadrature amplitudes. Moreover, based on density matrix renormalization group numerical calculations, endorsed by an analytical Gaussian approximation for the cavity state, we propose a direct link between those observables and quantum entropy singularities. We study two bipartite entanglement measures, the von Neumann and Rényi entanglement entropies, between light and matter subsystems. Even though both display singularities at the topological phase transition points, remarkably only the Rényi entropy can be analytically connected to the measurable Fano factor. Consequently, we show a method to recover the bipartite entanglement of the system from a cavity observable. Thus, we put forward a path to experimentally access the control and detection of a topological quantum phase transition via the Rényi entropy, which can be measured by standard low noise linear amplification techniques in superconducting circuits. In this way, the main quantum information features of Majorana polaritons in photon-fermion systems can be addressed in feasible experimental setups.

cond-mat.quant-gas↗