Publications Daniel GONZALEZ CUADRA

2023

Preprint

• T. Zache, D. Gonzalez Cuadra, P. Zoller Quantum and classical spin network algorithms for q-deformed Kogut-Susskind gauge theories, (2023-04-05), arXiv:2304.02527 arXiv:2304.02527 (ID: 721075) Toggle Abstract
  Treating the infinite-dimensional Hilbert space of non-abelian gauge theories is an outstanding challenge for classical and quantum simulations. Here, we introduce q-deformed Kogut-Susskind lattice gauge theories, obtained by deforming the defining symmetry algebra to a quantum group. In contrast to other formulations, our proposal simultaneously provides a controlled regularization of the infinite-dimensional local Hilbert space while preserving essential symmetry-related properties. This enables the development of both quantum as well as quantum-inspired classical Spin Network Algorithms for q-deformed gauge theories (SNAQs). To be explicit, we focus on SU(2)k gauge theories, that are controlled by the deformation parameter k and converge to the standard SU(2) Kogut-Susskind model as k→∞. In particular, we demonstrate that this formulation is well suited for efficient tensor network representations by variational ground-state simulations in 2D, providing first evidence that the continuum limit can be reached with k=O(10). Finally, we develop a scalable quantum algorithm for Trotterized real-time evolution by analytically diagonalizing the SU(2)k plaquette interactions. Our work gives a new perspective for the application of tensor network methods to high-energy physics and paves the way for quantum simulations of non-abelian gauge theories far from equilibrium where no other methods are currently available.

2022

Article

• J. Argüello-Luengo, Alejandro González-Tudela, Daniel Gonzalez Cuadra Tuning Long-Range Fermion-Mediated Interactions in Cold-Atom Quantum Simulators, Phys. Rev. Lett. 129 (2022-08-17), http://dx.doi.org/10.1103/PhysRevLett.129.083401 doi:10.1103/PhysRevLett.129.083401 (ID: 721044) Toggle Abstract
  Engineering long-range interactions in cold-atom quantum simulators can lead to exotic quantum many-body behavior. Fermionic atoms in ultracold atomic mixtures can act as mediators, giving rise to long-range Ruderman-Kittel-Kasuya-Yosida–type interactions characterized by the dimensionality and density of the fermionic gas. Here, we propose several tuning knobs, accessible in current experimental platforms, that allow one to further control the range and shape of the mediated interactions, extending the existing quantum simulation toolbox. In particular, we include an additional optical lattice for the fermionic mediator, as well as anisotropic traps to change its dimensionality in a continuous manner. This allows us to interpolate between power-law and exponential decays, introducing an effective cutoff for the interaction range, as well as to tune the relative interaction strengths at different distances. Finally, we show how our approach allows one to investigate frustrated regimes that were not previously accessible, where symmetry-protected topological phases as well as chiral spin liquids emerge.