arXiv subjects

R. Avella

Publications and source records attributed to R. Avella.

5 recordsLinked to original sources

arXiv2022

Density probabilities and quantum critical phenomena of a Bose-Fermi Mixture in 1D Double well potential

The time evolution of probability density, the ground-state fidelity and the entanglement of a Bose-Fermi mixture in a 1D double well potential, are studied through the two mode approximation. We found that the behaviour of the quantum return probability shows three distinct regions. The first region is characterized by a complete miscibility, and correlated tunneling of bosons and fermion. The second region is characterized by correlated sequential tunneling and in the last region we found an increase in the tunneling frequency of the two species. We found through the Von Neumann entropy, that the boson-fermion coupling allows a maximum entanglement of quantum correlations of bosons and fermions in the same value. Finally we calculated the fidelity in the $λ_{FF}-λ_{BF}$ and $λ_{BB}-λ_{BF}$ planes and we found that the drop of the two fidelities becomes deeper and deeper as the boson-fermion interaction decreases.

quant-ph↗

arXiv2021

Densities probabilities of a Bose-Fermi Mixture in 1D Double well potential

We use the two mode approximation for a interacting one-dimensional spinless soft core bosons and one half spin fermions in a double-well potential with a large central barrier. We include all the on-site boson-boson, fermion-fermion and boson-fermion repulsive contact potential represented by delta-function and considered bosonic and fermionic isotopes of ytterbium(Yb) $^{170}Yb$ and $^{171}Yb$ respectively. By means of the approximation, we find that in the regime $U_{BF}>U_{BB}$ give rise to a immiscible phase and in the regime $U_{BB}\geq U_{BF}$ give rise to a miscible phase, that is characterized by a temporal overlap of the bosonic and fermionic probability densities. We also report that due to the Bose-Fermi interaction, the system presents an apparent destruction of the collapse-revival oscillation of boson density probability at least in the ranges investigated.

cond-mat.quant-gas↗

arXiv2021

Bose-Fermi transmutation for one-dimensional harmonic trap

Using Density Matrix renormalization group (DMRG), we study the ground state properties of spin one-half fermions and scalar bosons in the soft-core limit, with weak s-wave inter and intra species interactions. We considered the system subject to one-dimensional (1D) optical lattice and a superimposed potential at zero temperature, in the framework of Bose-Fermi-Hubbard model. We found that for certain fillings and interaction parameters, a transmutation occurs between the ground states of bosons and fermions when the densities are exchanged. We too report that the density distributions of bosons and fermions overlap with each other in a bosonic and fermionic Mott plateau, when the interaction parameters fulfill the relationship $U_{BB}>U_{BF}<U_{BF}$. We also find that the fermions are repelled out of the central region of the trap for sufficiently strong $U_{FF}$ interaction, exhibiting phase separation of Bose and Fermi components.

cond-mat.quant-gas↗

arXiv2020

Mixture of scalar bosons and two-color fermions in one dimension: Superfluid-insulator transitions

Superfluid-insulator transitions in a one-dimensional mixture of two-color fermions and scalar bosons are studied within the framework of the Bose-Fermi-Hubbard model. Zero-temperature phase diagrams are constructed for repulsive intraspecies interactions and attractive or repulsive interspecies couplings. In addition to the trivial Mott insulator phases, we report the emergence of new non-trivial insulator phases that depend on the sign of the boson-fermion interaction. These non-trivial insulator phases satisfy the conditions $ρ_B\pmρ_F=n$ and $ρ_B\pm \tfrac{1}{2}ρ_F=n$, with the plus (minus) sign for repulsive (attractive) interactions and $n$ an integer. Far from fermionic half-filling, the boson-fermion interaction drives a gapless-gapped transition in the spin sector. Our findings could be observed experimentally in state-of-the-art cold-atom setups.

cond-mat.quant-gas↗

arXiv2019

Insulator phases of a mixture of spinor fermions and hard-core bosons

We study numerically a one-dimensional mixture of spin-$\tfrac{1}{2}$ fermions and scalar bosons in the hard-core limit. Considering repulsive fermion-fermion and boson-fermion interactions, we find superfluid and insulator states whose phase diagram is calculated. We determine that given a fermionic density $ρ_F$, the insulator states are located at the bosonic densities $ρ_B=1-ρ_F$ and $ρ_B=1-\tfrac{1}{2}ρ_F$, and emerge even in the absence of fermion-fermion coupling. In addition, the boson-fermion repulsion drives quantum phase transitions inside the insulator lobes with $ρ_B=1/2$. Our predictions could be observed in current cold-atom experimental platforms.

cond-mat.quant-gas↗