Questions tagged [optical-lattices]

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Getting the Bose-Hubbard Hamiltonian from cold atoms

In the famous paper by Dieter Jaksch, it is shown that the usual Hamiltonian for cold bosonic atoms interacting by s-wave scattering (Equation (1) in the paper): $$ \hat{H}=\int d^3 x\hat{\psi}^\...
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Optical trapping: factor 1/2 in definition of gradient force and potential energy?

If one consider the original deduction of the gradient forces that is applied to the trapped particle we can find the following: $$F_{grad}=\frac{1}{4} \alpha \nabla E_0^2(r),$$ where $E_0(r)$ is an ...
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31 views

Reduced absorption coefficient question

I came across a paper that reads It is noteworthy that for a sample without lateral light propagation in the material, i.e. [reduced scattering] $\mu_s' = \infty$ and [absorption] $\mu_a=0$, ... ...
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60 views

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 ...
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How do you find the 2nd order perturbed energy shift from the quantised dipole hamiltonian?

Without using the Rotating wave approximation how do you find the trapping potential $U(\mathbf r)$ experienced by an atom at position $\mathbf r$ for arbitrary laser frequencies? This can be done ...
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51 views

Why is matter wave field usually assumed to be be intrinsically stable?

In the paper "Collapse and revival of the matter wave field of a Bose-Einstein condensate" by M. Greiner, O. Mandel, T. Haensch and I. Bloch, it was stated that Bose-Einstein condensate (BEC) ...
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150 views

Numerical solution of driven infinite well with Floquet matrix

I am trying to understand and replicate figure 3 of this paper. The idea is that we have our box with a periodic drive $$H(t) = \frac{p^2}{2m}-F_0x\cos(\omega t)$$ The author states In order to ...
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286 views

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 ...
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1answer
85 views

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. (http://www.quantum.physik.uni-...
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51 views

can I make an optical lattice with a non Ti:Sapphire laser?

I am currently at a small undergraduate institution that does not have access to workhorses like a Ti:Saphire laser, however I am very interested in trying to make an optical lattice with lower power ...
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110 views

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 ...
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94 views

Bose-Hubbard Parameters from Band Structure

Could someone explain me how to compute numerically the parameters J and U and $\mu$ and the Wannier functions in the Bose-Hubbard model: $H=J\sum\limits_{j,1}^{L-1} (a_j^{+} a_{j+1}+ a_{j} a_{j+1}^{+...
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84 views

How to add Langevin terms to the semiclassical Bose-Hubbard model?

I would like to add Langevin terms to the Hamilton equations of motion of the semiclassical Bose-Hubbard model. Here's what I have: I start with the standard example of Brownian motion, a particle ...
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108 views

Novel atomic clocks: can quantum and many-body effects help?

I am trying to learn if there are any proposals concerning the application of quantum and many-body effects to atomic clocks. From what I understand, optical lattices have been used for timekeeping ...
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156 views

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\...
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165 views

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 ...