Browsing by Subject "Superfluidity"

Now showing 1 - 3 of 3

Open Access
Dark current control in InAs/GaSb superlattice photodetectors
(2013) Muti, Abdullah
Bose-Einstein Condensation (BEC) was introduced by Einstein 1925. It took 70 years to confirm BEC by experiments. BEC creates a suitable environment to observe macroscopic-quantum behavior. Condensates consist of ultracold atoms allow physicists to create superfluids and also they allow to manipulate these quantum structures easily. One of the main tool needed to manipulate these structures is synthetic magnetic field. Under the light of these experimental achievements we studied the angular momentum transfer in the N-body systems. First of all, to develop physical intuition, we solved 2-body problem. This problem can be defined as: The system consist of two particles and confined in a ring. Particles interact with each other and charged one coupled to the magnetic field. We used two approaches to solve the system and compared these approaches in the small limit of inter-particle interaction. Finally, we studied N-body systems and vortex transfer in the two-component superfluid mixtures via Gross-Pitaevski equation and Bogoulibov equations. We observed that for various parameters neutral-neutral mixtures do not possess vortex transfer, yet charged-neutral mixtures coupled to the magnetic field experience vortex transfer.
Open Access
Superfluid weight and polarization amplitude in the one-dimensional bosonic Hubbard model
(American Physical Society, 2019) Hetenyi, Balazs; Martelo, L. M.; Tanatar, Bilal
We calculate the superfluid weight and the polarization amplitude for the one-dimensional bosonic Hubbard model with focus on the strong-coupling regime via variational, exact diagonalization, and strong coupling calculations. Our variational approach is based on the Baeriswyl wave function, implemented via Monte Carlo sampling. We derive the superfluid weight appropriately in a variational setting. We emphasize the importance of implementing the Peierls phase in position space and to allow for many-body interference effects, rather than implementing the Peierls phase as single particle momentum shifts. At integer filling, the Baeriswyl wave function gives zero superfluid response at any coupling. At half filling our variational superfluid weight is in reasonable agreement with exact diagonalization results. We also calculate the polarization amplitude, the variance of the total position, and the associated size scaling exponent, which corroborate that this variational approach produces an insulating state at integer filling. Our Baeriswyl based variational method is applicable to significantly larger system sizes than exact diagonalization or quantum Monte Carlo.
Open Access
Vortex transfer in charged-neutral superfluid mixtures
(2013) Kaya, Semih
Bose-Einstein Condensation (BEC) was introduced by Einstein 1925. It took 70 years to confirm BEC by experiments. BEC creates a suitable environment to observe macroscopic-quantum behavior. Condensates consist of ultracold atoms allow physicists to create superfluids and also they allow to manipulate these quantum structures easily. One of the main tool needed to manipulate these structures is synthetic magnetic field. Under the light of these experimental achievements we studied the angular momentum transfer in the N-body systems. First of all, to develop physical intuition, we solved 2-body problem. This problem can be defined as: The system consist of two particles and confined in a ring. Particles interact with each other and charged one coupled to the magnetic field. We used two approaches to solve the system and compared these approaches in the small limit of inter-particle interaction. Finally, we studied N-body systems and vortex transfer in the two-component superfluid mixtures via Gross-Pitaevski equation and Bogoulibov equations. We observed that for various parameters neutral-neutral mixtures do not possess vortex transfer, yet charged-neutral mixtures coupled to the magnetic field experience vortex transfer.