What distinguishes trivial superfluids from topological superfluids in interacting many-body systems where the number of particles is conserved? Building on a class of integrable pairing Hamiltonians, we present a number-conserving, interacting variation of the Kitaev model, the Richardson-Gaudin-Kitaev chain, that remains exactly solvable for periodic and antiperiodic boundary conditions. Our model allows us to identify fermion parity switches that distinctively characterize topological superconductivity (fermion superfluidity) in generic interacting many-body systems. Although the Majorana zero modes in this model have only a power-law confinement, we may still define many-body Majorana operators by tuning the flux to a fermion parity switch. We derive a closed-form expression for an interacting topological invariant and show that the transition away from the topological phase is of third order.
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http://dx.doi.org/10.1103/PhysRevLett.113.267002 | DOI Listing |
Nat Phys
August 2024
Department of Physics, Harvard University, Cambridge, MA USA.
Commun Mater
October 2024
PSI Center for Neutron and Muon Sciences CNM, 5232 Villigen PSI, Switzerland.
The two-dimensional kagome lattice is an experimental playground for novel physical phenomena, from frustrated magnetism and topological matter to chiral charge order and unconventional superconductivity. A newly identified kagome superconductor, TaVSi has recently gained attention for possessing a record high critical temperature, = 7.5 K for kagome metals at ambient pressure.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
August 2024
Department of Physics and Astronomy, Center for Quantum Research and Technology, University of Oklahoma, Norman, OK 73069.
Excitons are the neutral quasiparticles that form when Coulomb interactions create bound states between electrons and holes. Due to their bosonic nature, excitons are expected to condense and exhibit superfluidity at sufficiently low temperatures. In interacting Chern insulators, excitons may inherit the nontrivial topology and quantum geometry from the underlying electron wavefunctions.
View Article and Find Full Text PDFJ Phys Condens Matter
July 2024
Department of Physics, University of California, Merced, CA 95343, United States of America.
The spatial Kibble-Zurek mechanism is applied to the Kitaev chain with inhomogeneous pairing interactions that vanish in half of the lattice and result in a quantum critical point separating the superfluid and normal-gas phases in real space. The weakly-interacting BCS theory predicts scaling behavior of the penetration of the pair wavefunction into the normal-gas region different from conventional power-law results due to the non-analytic dependence of the BCS order parameter on the interaction. The Bogoliubov-de Gennes (BdG) equation produces numerical results confirming the scaling behavior and hints complications in the strong-interaction regime.
View Article and Find Full Text PDFPhys Rev Lett
June 2024
Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
The Kibble-Zurek mechanism (KZM) describes the nonequilibrium dynamics and topological defect formation in systems undergoing second-order phase transitions. KZM has found applications in fields such as cosmology and condensed matter physics. However, it is generally not suitable for describing first-order phase transitions.
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