Questions tagged [lattice-model]
Lattice is a way of discretizing a quantum field theory for numerical simulations.
476 questions
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How to define an effective light cone or null direction from discrete arrival times on a lattice?
In several discrete or lattice-based approaches to spacetime (causal sets, Regge-like discretizations, lattice field theory, numerical GR, fast-marching/eikonal methods), one often works with a ...
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Reweighting method for Metropolis algorithm
I read the Wiki page about the reweighting procedure as a way to use Monte Carlo methods with the sign problem, but I'd like to know more about how this could be implemented in the Metropolis ...
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Creutz, "Quarks, Gluons And Lattices", equations (5.31), (5.32). Struggling to prove them [duplicate]
I've realised that this question is a duplicate of Proof involving exponential of anticommuting operators, where one can find some answer.
I'm struggling to show the equations mentionned in the title. ...
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$\phi^4$ theory lattice propagator
I'm simulating $\phi^4$ quantum field theory in real-time on the lattice.
My lattice action:
$$S=\sum_{x}\sum_{μ}η_{μμ}\frac{(\phi_{x+μ}-\phi_x)^2}{2}-\frac{(m^2+iε)}{2}\phi_{x}^2-\frac{λ}{4}\phi_{x}^...
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Spacetime as a lattice in classical mechanics
I am currently studying lattice methods to be able to apply them to lattice QCD later. In order to get a good intuition, I deem it adequate to do the following exercise: I would like to formulate the ...
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Does QFT predict that the lattice constant of the universe is zero?
The title might be confusing, so let me explain.
Planck unknowingly started the field of quantum mechanics when he described blackbody radiation spectra using a law that assumes discrete values for ...
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How to make sense of non-planar Wilson loops on the lattice?
I am operating with a (more or less standard) Metropolis+Overrelaxation algorithm a series of Wilson loops on a $N_t\times N_s^2=48^2\times 16$ (2+1) dimensional Euclidean lattice. I am simulating ...
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Extracting decay rates and cross sections from finite time correlation functions
Is it possible to extract decay rates or cross sections from finite volume lattice QFT in minkowski space time? (Suppose i have simulated such a system, and i have correlation functions available)
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Is it possible to analytically continue magnetization in one-dimensional Ising models?
I am asking about the infinitely long layered Ising model with a finite number of layers. The model is assumed to be invariant under translations along the direction in which it is infinite. All ...
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Lattice Hamiltonian From $SU(2)_{k}$ Current
Suppose I have a theory built from a $SU(2)_{k}$ currents $\mathbf{J}$ with a simple form of
Hamiltonian like:
$$
H \sim \mathbf{J.J}
$$
How can I write this Hamiltonian based on spin operators on a ...
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Can the index in the pre-exponential factor in the correlation function depend on the direction?
There is quite a lot of discussion on SE about correlation functions in lattice models. So I would say that it is well known that the two-spin (two-point) correlation function has the following ...
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Confused regarding packing fraction of 2D Hexagonal closed packing
Ok so I was doing a few questions on Solid State and Lattice points, I encountered a doubt. My book says the packing efficiency in 2D hexagonal closed packing is 𝛑/2sqrt(3). When I looked up the ...
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How to Calculate Virasoro's Characters of Critical 3-state Pott's model without Considering $W$ algebra?
Let's consider the critical 3-state Potts model. According to conformal field theory, it corresponds to a CFT with a central charge $c=\frac{4}{5}$. However, there are 10 characters for $c=\frac{4}{5}$...
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Simple proof of a high temperature disordered phase for the Ising model
The original (and probably simplest) argument for the existence of an ordered phase for the Ising model at low (but non-zero) temperature was the Peirls argument, where you basically give an upper ...
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Do the momentum values and the winding numbers in a compactified string theory be periodic too(along with being discrete)?
I have a question. In lattice qcd, we compactify space to make it periodic. Also because of the formation of the reciprocal brilliouin zone, even momentum becomes discrete valued and periodic. Because ...
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