Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userStuckelberg interferometry using spin-orbit-coupled cold atoms in an optical lattice
107
0
0.0
(
0
)
Ask ChatGPT about the research
No Arabic abstract
Time evolution of spin-orbit-coupled cold atoms in an optical lattice is studied, with a two-band energy spectrum having two avoided crossings. A force is applied such that the atoms experience two consecutive Landau-Zener tunnelings while transversing the avoided crossings. Stuckelberg interference arises from the phase accumulated during the adiabatic evolution between the two tunnelings. This phase is gauge field-dependent and thus provides new opportunities to measure the synthetic gauge field, which is verified via calculation of spin transition probabilities after a double passage process. Time-dependent and time-averaged spin probabilities are derived, in which resonances are found. We also demonstrate chiral Bloch oscillation and rich spin-momentum locking behavior in this system.
rate research
Read More
Engineered spin-orbit coupling (SOC) in cold atom systems can aid in the study of novel synthetic materials and complex condensed matter phenomena. Despite great advances, alkali atom SOC systems are hindered by heating from spontaneous emission, which limits the observation of many-body effects, motivating research into potential alternatives. Here we demonstrate that SOC can be engineered to occur naturally in a one-dimensional fermionic 87Sr optical lattice clock (OLC). In contrast to previous SOC experiments, in this work the SOC is both generated and probed using a direct ultra-narrow optical clock transition between two electronic orbital states. We use clock spectroscopy to prepare lattice band populations, internal electronic states, and quasimomenta, as well as to produce SOC dynamics. The exceptionally long lifetime of the excited clock state (160 s) eliminates decoherence and atom loss from spontaneous emission at all relevant experimental timescales, allowing subsequent momentum- and spin-resolved in situ probing of the SOC band structure and eigenstates. We utilize these capabilities to study Bloch oscillations, spin-momentum locking, and Van Hove singularities in the transition density of states. Our results lay the groundwork for the use of OLCs to probe novel SOC phases of matter.
The Zitterbewegung effect in spin-orbit coupled spin-1 cold atoms is investigated in the presence of the Zeeman field and a harmonic trap. It is shown that the Zeeman field and the harmonic trap have significant effect on the Zitterbewegung oscillatory behaviors. The external Zeeman field could suppress or enhance the Zitterbewegung amplitude and change the frequencies of oscillation. A much slowly damping Zitterbewegung oscillation can be achieved by adjusting both the linear and quadratic Zeeman field. Multi-frequency Zitterbewegung oscillation can be induced by the applied Zeeman field. In the presence of the harmonic trap, the subpackets corresponding to different eigenenergies would always keep coherent, resulting in the persistent Zitterbewegung oscillations. The Zitterbewegung oscillation would display very complicated and irregular oscillation characteristics due to the coexistence of different frequencies of the Zitterbewegung oscillation. Numerical results show that, the Zitterbewegung effect is robust even in the presence of interaction between atoms.
Motivated by recent experimental development, we investigate spin-orbit coupled repulsive Fermi atoms in a one-dimensional optical lattice. Using the density-matrix renormalization group method, we calculate momentum distribution function, gap, and spin-correlation function to reveal rich ground-state properties. We find that spin-orbit coupling (SOC) can generate unconventional momentum distribution, which depends crucially on the filling. We call the corresponding phase with zero gap the SOC-induced metallic phase. We also show that SOC can drive the system from the antiferromagnetic to ferromagnetic Mott insulators with spin rotating. As a result, a second-order quantum phase transition between the spin-rotating ferromagnetic Mott insulator and the SOC-induced metallic phase is predicted at the strong SOC. Here the spin rotating means that the spin orientations of the nearest-neighbor sites are not parallel or antiparallel, i.e., they have an intersection angle $theta in (0,pi )$. Finally, we show that the momentum $k_{mathrm{peak}}$, at which peak of the spin-structure factor appears, can also be affected dramatically by SOC. The analytical expression of this momentum with respect to the SOC strength is also derived. It suggests that the predicted spin-rotating ferromagnetic ($k_{mathrm{peak}% }<pi /2$) and antiferromagnetic ($pi /2<k_{mathrm{peak}}<pi $) correlations can be detected experimentally by measuring the SOC-dependent spin-structure factor via the time-of-flight imaging.
We study the dynamical behaviour of ultracold fermionic atoms loaded into an optical lattice under the presence of an effective magnetic flux, induced by spin-orbit coupled laser driving. At half filling, the resulting system can emulate a variety of iconic spin-1/2 models such as an Ising model, an XY model, a generic XXZ model with arbitrary anisotropy, or a collective one-axis twisting model. The validity of these different spin models is examined across the parameter space of flux and driving strength. In addition, there is a parameter regime where the system exhibits chiral, persistent features in the long-time dynamics. We explore these properties and discuss the role played by the systems symmetries. We also discuss experimentally-viable implementations.
We investigate the Fermi polaron problem in a spin-1/2 Fermi gas in an optical lattice for the limit of both strong repulsive contact interactions and one dimension. In this limit, a polaronic-like behaviour is not expected, and the physics is that of a magnon or impurity. While the charge degrees of freedom of the system are frozen, the resulting tight-binding Hamiltonian for the impuritys spin exhibits an intriguing structure that strongly depends on the filling factor of the lattice potential. This filling dependency also transfers to the nature of the interactions for the case of two magnons and the important spin balanced case. At low filling, and up until near unit filling, the single impurity Hamiltonian faithfully reproduces a single-band, quasi-homogeneous tight-binding problem. As the filling is increased and the second band of the single particle spectrum of the periodic potential is progressively filled, the impurity Hamiltonian, at low energies, describes a single particle trapped in a multi-well potential. Interestingly, once the first two bands are fully filled, the impurity Hamiltonian is a near-perfect realisation of the Su-Schrieffer-Heeger model. Our studies, which go well beyond the single-band approximation, that is, the Hubbard model, pave the way for the realisation of interacting one-dimensional models of condensed matter physics.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
