A lattice formed by the interference of counter-propagating laser beams, creating a spatially periodic polarisation pattern, which may be used to trap neutral atoms via the AC Stark shift to perform quantum simulation experiments or build atomic clocks.
Questions tagged [optical-lattices]
35 questions
4
votes
1 answer
In AMO experiments, how do cold alkali metal atoms remain gaseous?
My focus is on condensed matter physics, so I've never really explored this question although it always seemed curious to me. My "immediate reaction" intuition would dictate that cold metal atoms would come together to form a metal, but obviously…
BGreen
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4
votes
1 answer
Symmetry breaking and Superfluid - Mott Insulator transition
I know my question is similar to what mentioned in this post:
Symmetry breaking in Bose-Hubbard model.
Yet, I don't find it clear. I've in mind a 1D Bose-Hubbard Hamiltonian. Moving from the Mott Insulator phase to the Superfluid Phase, a…
AndreaPaco
- 1,322
4
votes
1 answer
Is Bose-Einstein condensate in the optical lattice a single mode condensate?
I recently read about BEC loaded into the optical lattice p.200
Looking at a condensate released from a lattice after a
time of flight typically on the order of a few milliseconds
amounts to observing its momentum
distribution. A harmonically…
WoofDoggy
- 2,190
3
votes
1 answer
Floquet bandstructure calculation
In this paper "Photonic Floquet Topological Insulators" the authors calculate the bandstructure of a time-periodic Hamiltonian. They create a time-dependent tight-binding Hamiltonian via the Peierl's substitution.
Now my first question would be…
JanJasper
- 33
3
votes
1 answer
Can one make a synthetic dimension "curl around" into a cylinder?
A really cool recent proposal,
Synthetic Gauge Fields in Synthetic Dimensions. A. Celi et al. Phys. Rev. Lett. 112, 043001 (2014), arXiv:1307.8349,
shows how you can simulate a synthetic magnetic field in a fictional 2D lattice by taking a 1D…
Emilio Pisanty
- 137,480
2
votes
0 answers
Why do the quasienergies arising from the Floquet theorem behave like energies
It's well established that an optical tweezer and optical lattices can trap atoms. The typical explanation for this is that the AC stark shift creates a position-dependent energy which can be interpreted as a potential that the atom moves in.
I've…
AXensen
- 8,778
2
votes
0 answers
Equivalence between rotation and magnetic flux in lattice models
I am trying to understand the presence of complex hopping amplitudes in Hubbard-like lattice models. The hopping term features the so called "Peierls phase":
$$
- t\sum_{j=1}^L \left( c_{j+1}^\dagger c_{j} e^{+i\frac{\Phi}{L}} + c_{j}^\dagger…
AndreaPaco
- 1,322
2
votes
2 answers
What wavelengths are used practically in optical trapping?
I am currently working on my Master thesis in a cold atom research group, and have irritatingly found -- or rather not found -- that no book or paper seems to explicitly mention what wavelengths are typically used for optical trapping. Our group…
John Doe
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2
votes
2 answers
Lattice vs Superlattice
What is the difference between lattice and superlattice ? Can anyone describe with a schematic figure? I have encountered superlattice in the context of bose hubbard model. Also what are the advantages or disadvantages in superlattice compared to…
2
votes
1 answer
Time of flight images of Bose-Hubbard model
on the website of Immanuel Bloch, you can find time of flight images of bosonic particles inside an optical lattice for different values of the depth of the lattice.…
QuantumMechanics
- 568
2
votes
0 answers
Are Dirac points the norm for 2D band structure?
I've been doing simulations of band structure for 2D optical lattices, and something I've noticed is that, for sufficiently shallow lattices, there are typically points on the edge of the first Brillouin zone where the lowest bands touch (or nearly…
Yly
- 3,729
2
votes
0 answers
Ground state symmetry breaking in Bose-Hubbard model with spin-orbit coupling
The Hamiltonian for 2D Bose-Hubbard model with spin-orbit coupling on a square lattice is written as
$
H = -t\sum_{\langle ij \rangle}\Psi_i^{\dagger}\Psi_j^{\vphantom{\dagger}}
+ \frac{U}{2}\sum_{i\sigma}n_{i\sigma}(n_{i\sigma}-1)
+ U_{\uparrow…
Timothy
- 2,539
1
vote
0 answers
The definitions of coherent phonons and acoustic phonons
I found that the definition of coherent phonon: A femtosecond laser pulse can initiate collective, in-phase atomic motions in solids called coherent phonons.
My question is: what is the difference between coherent phonons and acoustic…
MathJacky
- 21
1
vote
1 answer
What does "address" mean in "addressing lattice sites"?
In an abstract about "Sub-lattice-resolved imaging", the author was talking about local addressing of individual lattice sites:
Here we introduce an imaging approach where matter wave optics magnifies the density distribution prior to optical…
Ahmed Samir
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1
vote
2 answers
Is it possible to laser cool without using spatially-varying magnetic fields and above zero degrees?
As the title says, is it possible to laser cool without generating a weak quadrupolar magnetic field? Also, if I wasn't trying to achieve extremely low temperatures is it possible to use laser cooling when gas temps are above 0 degrees? If not, why…
G Gr
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