We discuss how entanglement of strongly correlated fermions is influenced by a superlattice structure by considering a one-dimensional Hubbard superlattice, made up of a repeated pattern of ${L}_{U}$ repulsive sites followed by ${L}_{0}$ free sites. Lanczos diagonalization of lattices up to 24 sites is used to calculate the von Neumann entropy and the negativity. The breakdown of particle-hole symmetry broadens the maxima of the entropy in the underdoped region, while the entanglement in the overdoped region is crucially influenced by the nature of the magnetic state, with dips at densities corresponding to repulsive-layer singlets and to $q=\ensuremath{\pi}$ (in units of inverse unit cell length, ${L}_{U}+{L}_{0}$ ) spin-density waves. At these special densities, the system is either a Mott insulator or a ``compressible insulator.'' We have also found that sites within the same repulsive layer (for ${L}_{U}\ensuremath{\ge}2$) are monogamically entangled with each other, which may provide a route to control entanglement simultaneously in different length scales.We discuss how entanglement of strongly correlated fermions is influenced by a superlattice structure by considering a one-dimensional Hubbard superlattice, made up of a repeated pattern of ${L}_{U}$ repulsive sites followed by ${L}_{0}$ free sites. Lanczos diagonalization of lattices up to 24 sites is used to calculate the von Neumann entropy and the negativity. The breakdown of particle-hole symmetry broadens the maxima of the entropy in the underdoped region, while the entanglement in the overdoped region is crucially influenced by the nature of the magnetic state, with dips at densities corresponding to repulsive-layer singlets and to $q=\ensuremath{\pi}$ (in units of inverse unit cell length, ${L}_{U}+{L}_{0}$) spin-density waves. At these special densities, the system is either a Mott insulator or a ``compressible insulator.'' We have also found that sites within the same repulsive layer (for ${L}_{U}\ensuremath{\ge}2$) are monogamically entangled with each other, which may provide a route to control entanglement simultaneously in different length scales.

Physical Review BJun 7, 201312 citations

Fast collisional $\sqrt{\mathrm{SWAP}}$ gate for fermionic atoms in an optical superlatticeFast collisional $\sqrt{\mathrm{SWAP}}$ gate for fermionic atoms in an optical superlattice

Rafi Weill, Jonathan Nemirovsky, Yoav Sagi

Collisional gates in optical superlattices have recently achieved record fidelities, but their operation times are typically limited by tunneling. Here we propose and analyze an alternative route to a fast $\sqrt{\mathrm{SWAP}}$ gate for two fermionic atoms in an optical superlattice based on optimized, time-dependent control of the short and long lattice depths. The gate is implemented by transiently releasing the atoms into a quasi-harmonic confinement centered between the two sites. With an appropriately chosen contact interaction strength, a controlled collision accumulates the exchange phase required for $\sqrt{\mathrm{SWAP}}$ and generates entanglement. We employ a continuum, time-dependent Schrödinger-equation simulation that goes beyond a two-site Fermi--Hubbard description and benchmark it against experimentally implemented tunneling-based protocols, reproducing the observed single-particle tunneling and spin-exchange dynamics. For experimentally accessible lattice depths, we find that the proposed gate operates in $\sim 21\,μ\mathrm{s}$ , more than an order of magnitude faster than tunneling-based implementations, while achieving fidelities $\gtrsim 99\%$ . We further analyze sensitivity to lattice-depth variations and show that a composite sequence improves robustness. Our results establish fast, collision-mediated entangling gates in superlattices as a promising building block for scalable neutral-atom quantum computation.Collisional gates in optical superlattices have recently achieved record fidelities, but their operation times are typically limited by tunneling. Here we propose and analyze an alternative route to a fast $\sqrt{\mathrm{SWAP}}$ gate for two fermionic atoms in an optical superlattice based on optimized, time-dependent control of the short and long lattice depths. The gate is implemented by transiently releasing the atoms into a quasi-harmonic confinement centered between the two sites. With an appropriately chosen contact interaction strength, a controlled collision accumulates the exchange phase required for $\sqrt{\mathrm{SWAP}}$ and generates entanglement. We employ a continuum, time-dependent Schrödinger-equation simulation that goes beyond a two-site Fermi--Hubbard description and benchmark it against experimentally implemented tunneling-based protocols, reproducing the observed single-particle tunneling and spin-exchange dynamics. For experimentally accessible lattice depths, we find that the proposed gate operates in $\sim 21\,μ\mathrm{s}$, more than an order of magnitude faster than tunneling-based implementations, while achieving fidelities $\gtrsim 99\%$. We further analyze sensitivity to lattice-depth variations and show that a composite sequence improves robustness. Our results establish fast, collision-mediated entangling gates in superlattices as a promising building block for scalable neutral-atom quantum computation.

cond-mat.quant-gasCross-listedarXiv:2512.22569Physical Review ADec 30, 20251 citation

Entanglement detachment in fermionic systems

Hernán Santos, J. E. Alvarellos, Javier Rodríguez-Laguna

arXiv:1809.06793The European Physical Journal DNov 1, 20181 citation

Entanglement in Fermionic Chains and Bispectrality

Nicolas Crampé, Rafael I. Nepomechie, Luc Vinet

WORLD SCIENTIFIC eBooksJul 20, 202010 citations

Entanglement in Spatially Inhomogeneous Many-Fermion Systems

V. V. França, Klaus Capelle

We investigate entanglement of strongly interacting fermions in spatially inhomogeneous environments. To quantify entanglement in the presence of spatial inhomogeneity, we propose a local-density approximation (LDA) to the entanglement entropy, and a nested LDA scheme to evaluate the entanglement entropy on inhomogeneous density profiles. These ideas are applied to models of electrons in superlattice structures with different modulation patterns, electrons in a metallic wire in the presence of impurities, and phase-separated states in harmonically confined many-fermion systems, such as electrons in quantum dots and atoms in optical traps. We find that the entanglement entropy of inhomogeneous systems is strikingly different from that of homogeneous systems.We investigate entanglement of strongly interacting fermions in spatially inhomogeneous environments. To quantify entanglement in the presence of spatial inhomogeneity, we propose a local-density approximation (LDA) to the entanglement entropy, and a nested LDA scheme to evaluate the entanglement entropy on inhomogeneous density profiles. These ideas are applied to models of electrons in superlattice structures with different modulation patterns, electrons in a metallic wire in the presence of impurities, and phase-separated states in harmonically confined many-fermion systems, such as electrons in quantum dots and atoms in optical traps. We find that the entanglement entropy of inhomogeneous systems is strikingly different from that of homogeneous systems.

arXiv:0710.2095Physical Review LettersFeb 21, 200856 citations

We discuss how entanglement of strongly correlated fermions is influenced by a superlattice structure by considering a one-dimensional Hubbard superlattice, made up of a repeated pattern of

{L}_{U}

repulsive sites followed by

{L}_{0}

free sites. Lanczos diagonalization of lattices up to 24 sites is used to calculate the von Neumann entropy and the negativity. The breakdown of particle-hole symmetry broadens the maxima of the entropy in the underdoped region, while the entanglement in the overdoped region is crucially influenced by the nature of the magnetic state, with dips at densities corresponding to repulsive-layer singlets and to $q=\ensuremath{\pi}$ (in units of inverse unit cell length,

{L}_{U}+{L}_{0}

) spin-density waves. At these special densities, the system is either a Mott insulator or a ``compressible insulator.'' We have also found that sites within the same repulsive layer (for ${L}_{U}\ensuremath{\ge}2$) are monogamically entangled with each other, which may provide a route to control entanglement simultaneously in different length scales.

Fast collisional

\sqrt{\mathrm{SWAP}}

gate for fermionic atoms in an optical superlattice

\sqrt{\mathrm{SWAP}}

gate for two fermionic atoms in an optical superlattice based on optimized, time-dependent control of the short and long lattice depths. The gate is implemented by transiently releasing the atoms into a quasi-harmonic confinement centered between the two sites. With an appropriately chosen contact interaction strength, a controlled collision accumulates the exchange phase required for

\sqrt{\mathrm{SWAP}}

and generates entanglement. We employ a continuum, time-dependent Schrödinger-equation simulation that goes beyond a two-site Fermi--Hubbard description and benchmark it against experimentally implemented tunneling-based protocols, reproducing the observed single-particle tunneling and spin-exchange dynamics. For experimentally accessible lattice depths, we find that the proposed gate operates in

\sim 21\,μ\mathrm{s}

, more than an order of magnitude faster than tunneling-based implementations, while achieving fidelities

\gtrsim 99\%

. We further analyze sensitivity to lattice-depth variations and show that a composite sequence improves robustness. Our results establish fast, collision-mediated entangling gates in superlattices as a promising building block for scalable neutral-atom quantum computation.