@inproceedings {puspus-spp-2015, title = {R{\'e}nyi entanglement entropy of the spin-partitioned BCS ground state}, booktitle = {Proceedings of the 33rd Samahang Pisika ng Pilipinas Physics Congress}, year = {2015}, month = {3{\textendash}6 Jun 2015}, pages = {spp-2015-2B-03}, address = {University of Northern Philippines, Vigan City}, abstract = {
We use the R{\'e}nyi entanglement entropy to study entanglement between the spin components of the Bardeen-Cooper-Schrieffer (BCS) ground state and we characterize its limiting values. We show that R{\'e}nyi entropies peak in the region about the Fermi surface. We also show that the orbital single-copy entanglement can be interpreted as the thermodynamic free energy of a two-level system at thermal equilibrium. We observed that the total R{\'e}nyi-2 entropy and the total single-copy entanglement are proportional to the number of electron orbitals having energies about the Fermi energy.
}, author = {Xavier M Puspus and Francis N. C. Paraan} } @article {Puspus2014, title = {Entanglement spectrum and number fluctuations in the spin-partitioned BCS ground state}, journal = {Phys. Rev. B}, volume = {90}, number = {15}, year = {2014}, note = {cited By 2}, pages = {155123}, abstract = {
We study entanglement between the spin components of the BCS ground state by calculating the full entanglement spectrum and the corresponding von Neumann entanglement entropy. The entanglement spectrum is effectively modeled by a generalized Gibbs ensemble (GGE) of noninteracting electrons, which may be approximated by a canonical ensemble at the BCS critical temperature. We further demonstrate that the entanglement entropy is jointly proportional to the pairing energy and to the number of electrons about the Fermi surface (an area law). Furthermore, the entanglement entropy is also proportional to the number fluctuations of either spin component in the BCS state.
}, doi = {10.1103/PhysRevB.90.155123}, author = {Xavier M Puspus and Kristian Hauser Villegas and Francis N. C. Paraan} } @inproceedings {puspus-spp-2013, title = {Entanglement entropy of impenetrable bosons in 1D: Effects of block length and boundaries}, booktitle = {Proceedings of the 31st Samahang Pisika ng Pilipinas Physics Congress}, year = {2013}, month = {23{\textendash}25 Oct 2013}, pages = {SPP2013-3B-7}, address = {University of San Carlos, Cebu City}, abstract = {
The effects of block length and boundary conditions on the entanglement entropy of two impenetrable bosons in separate spatial partitions of finite extent are studied in this paper. The von Neumann and R{\'e}nyi entropies decreased monotonically as the lengths of the block and environment become more and more unequal. Also, the system with periodic boundary conditions possesses a larger entanglement entropy than that with open boundaries.
}, author = {Xavier M Puspus and Francis N. C. Paraan} }