LPT Toulouse - FFC Journal Club | 09.01.2023 | J. Colbois
arXiv:2211.13089 (v1)
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Need
Idea
Promise
M
+ Combine efficiently
\(10^9\) non-interacting
\(10^6\) Two interacting particles
Time evolution
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(1) Mostly: \(t_{i, i+1} = t = 1\), \(\epsilon_i \) :
Irrational \(\beta\)
(2) Also:
\(\epsilon_i\) constant
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arXiv:2211.13089 (v1)
(1) Mostly: \(t_{i, i+1} = t = 1\), \(\epsilon_i \) :
Irrational \(\beta\)
(2) Also:
\(\epsilon_i\) constant
More delocalized
Chiral (particle-hole) symmetry:
Delocalized region
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Only at strong disorder
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Density of states
Localization length
Participation ratio
D J Thouless 1972 J. Phys. C: Solid State Phys. 5 77
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Parallelization
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Repetitions
\(L-M\) sub-systems
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Repetitions
\(L-M\) sub-systems
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arXiv:2211.13089 (v1)
Repetitions
\(L-M\) sub-systems
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Repetitions
\(L-M\) sub-systems
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arXiv:2211.13089 (v1)
Repetitions
\(L-M\) sub-systems
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arXiv:2211.13089 (v1)
Repetitions
\(L-M\) sub-systems
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arXiv:2211.13089 (v1)
Repetitions
\(L-M\) sub-systems
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Repetitions
\(L-M\) sub-systems
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Repetitions
\(L-M\) sub-systems
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\(\left \lceil \frac{2L}{M}\right\rceil \) sub-systems
Far less repetitions
\(M \) twice as large
Repetitions
\(L-M\) sub-systems
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arXiv:2211.13089 (v1)
\(\left \lceil \frac{2L}{M}\right\rceil \) sub-systems
Far less repetitions
\(M \) twice as large
Repetitions
\(L-M\) sub-systems
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arXiv:2211.13089 (v1)
\(\left \lceil \frac{2L}{M}\right\rceil \) sub-systems
Far less repetitions
\(M \) twice as large
Repetitions
\(L-M\) sub-systems
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arXiv:2211.13089 (v1)
\(\left \lceil \frac{2L}{M}\right\rceil \) sub-systems
Far less repetitions
\(M \) twice as large
Repetitions
\(L-M\) sub-systems
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arXiv:2211.13089 (v1)
\(\left \lceil \frac{2L}{M}\right\rceil \) sub-systems
Far less repetitions
\(M \) twice as large
Repetitions
\(L-M\) sub-systems
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arXiv:2211.13089 (v1)
\(\left \lceil \frac{2L}{M}\right\rceil \) sub-systems
Far less repetitions
\(M \) twice as large
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Real
Spurious
\(B_{i-1}\)
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\(|\Phi\rangle\) localized in \(S\) :
Variance w.r.t environment
\(|\Phi\rangle\) eigenvector of \( H^S\):
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arXiv:2211.13089 (v1)
Alternative : Gram-Schmidt
Two steps:
No arbitrary cut-off
Much slower
1. \( |E_{\Phi} - E_{\Phi_k}| > \mathrm{num. }\, \mathrm{err} \quad \forall \, k \in \mathrm{rel.}\, \mathrm{clusters} \)
2. \( \langle \Phi_{j} | \Phi \rangle < \theta \) for all relevant \(k\)
\( \Rightarrow | \Phi \rangle \) is a new eigenfunction
Setting \(\theta\) :
Pop. on each site should not be larger than 1.
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arXiv:2211.13089 (v1)
Two steps:
1. \( |E_{\Phi} - E_{\Phi_k}| > \mathrm{num. }\, \mathrm{err} \quad \forall \, k \in \mathrm{rel.}\, \mathrm{clusters} \)
2. \( \langle \Phi_{j} | \Phi \rangle < \theta \) for all relevant \(k\)
\( \Rightarrow | \Phi \rangle \) is a new eigenfunction
Setting \(\theta\) :
Pop. on each site should not be larger than 1.
Parallelization:
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Prec. \(\epsilon\) on \(\langle\hat{O}\rangle\) \(\Rightarrow\)
# Eigenfunctions:
Accuracy of eigenfunctions:
Valid eigenfunctions : variance smaller than \(\delta^2\)
(Err. \(\delta\) in amplitude)
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\( S = [\alpha, \Omega]\)
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Here \(|\Phi_{i}| ^2 = \sum_{j} |\langle i,j |\Phi\rangle |^2 \)
Smaller than a given cut-off.
Increase \(M\): new eigenstates, but independent of the value of the interaction
arXiv:2211.13089 (v1)
Parameters
\(\sigma\)
\(\theta, \, \delta (\epsilon)\)
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\(M_{\mathrm{Max}} = 26000 \)
\(\Rightarrow V_{\mathrm{Min}} = 0.05 \): \(W^{\mathrm{box}}_{\mathrm{And.}} \sim 0.77\); \(W^{\mathrm{Gauss.}}_{\mathrm{And.}} = W^{\mathrm{Bin.}}_{\mathrm{And.}} \sim 0.44\)
Variance:
Time evolution:
\(M_{\mathrm{Max}} = 200 \)
Variance:
Overlap:
\(\theta = 10^{-5}\)
Overlap:
\(\theta = 10^{-7}\)
Time evolution:
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\(M \propto \xi \)
Assume
Limitations:
\(\xi \sim L\) (ergodic) \(\rightarrow\) usual complexity
\(\xi \ll L\) \(\rightarrow\) Dep. \(L\) : locally larger \(M\)
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4 cores Inter Core i7-7700 CPU
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\(M\)
Potential variance
arXiv:2211.13089 (v1)
S. Aubry and G. André, Ann. Israel Phys. Soc 3, 18, (1980)
Strong
Weak
Single Particle
Two Interacting Particles
Eigenfunctions / Dynamics
Disorder
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\(10^9\) sites, Box distribution
\(W_{\mathrm{And.}} = 10\)
\(W_{\mathrm{MBL}} = 2.5\)
\(W_{\mathrm{And.}} = 20\)
\(W_{\mathrm{MBL}} = 5\)
\(W_{\mathrm{And.}} = 40\)
\(W_{\mathrm{MBL}} = 10\)
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Diff.
\(U = 0\)
\(U = 2\)
\(L = 10^5, W_{\mathrm{And.}} = 10\)
Box distribution
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\( U = 10, L = 10^6, W_{\mathrm{And.}} = 40\)
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\( U = 10, L = 10^6, W_{\mathrm{And.}} = 40\)
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D.O.S., \(V = 0.05\), i.e. \(W_{\mathrm{Box, MBL}} = \) ; \(L = 10^8\) sites
arXiv:2211.13089 (v1)
Cusp : M. Kappus and F. Wegner,
Zeit. Phys. B 45,15–21 (1981)
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Localization length, \(V = 0.05\), i.e. \(W_{\mathrm{Box, MBL}} = \) ; \(L = 10^8\) sites
arXiv:2211.13089 (v1)
G. Czycholl, B. Kramer, and A. MacKinnon, Zeit. Phys. B 43, 5–11 (1981)
M. Kappus and F. Wegner, Zeit. Phys. B 45,15–21 (1981)
B. Kramer and A. MacKinnon, Rep. Prog. Phys. 56, 1469 (1993)
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Localization length, \(L = 10^8\) sites
arXiv:2211.13089 (v1)
G. Czycholl, B. Kramer, and A. MacKinnon, Zeit. Phys. B 43, 5–11 (1981)
M. Kappus and F. Wegner, Zeit. Phys. B 45,15–21 (1981)
B. Kramer and A. MacKinnon, Rep. Prog. Phys. 56, 1469 (1993)
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\(L = 10^8\), Box distribution, \(V = 0.05\)
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\(L = 10^8\), Box distribution, \(V = 0.05\)
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\(L = 10^8\), Box distribution, \(V = 0.05\)
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\(L = 10^6\), \(W_{\mathrm{And}} = 4\)
\(V = 4\)
\(L = 10^6\), \(W_{\mathrm{And}} = 6\)
\(V = 3\)
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\(L = 10^6\), \(W_{\mathrm{And}} = 4\)
\(V = 4\)
\(L = 10^6\), \(W_{\mathrm{And}} = 6\)
\(V = 3\)
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\(L = 10^6\), \(W_{\mathrm{And}} = 4\)
\(V = 4\)
\(L = 10^6\), \(W_{\mathrm{And}} = 6\)
\(V = 3\)
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\(L = 10^6\), \(W_{\mathrm{And}} = 6\)
\(V = 3\)
\(L = 10^6\), \(W_{\mathrm{And}} = 4\)
\(V = 4\)
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\(L = 10^6\), \(W_{\mathrm{And}} = 6\)
\(V = 3\)
\(L = 10^6\), \(W_{\mathrm{And}} = 4\)
\(V = 4\)
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\(L = 10^6\), \(W_{\mathrm{And}} = 6\)
\(V = 3\)
\(L = 10^6\), \(W_{\mathrm{And}} = 4\)
\(V = 4\)
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\(L = 10^6\), \(W_{\mathrm{And}} = 6\)
\(V = 3\)
\(L = 10^6\), \(W_{\mathrm{And}} = 4\)
\(V = 4\)
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Aubry-André model
\(L = 10^8\) sites
S. Aubry and G. André, Ann. Israel Phys. Soc 3, 18, (1980)
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Bond disorder
\(L = 10^8\) sites
arXiv:2211.13089 (v1)
\(M = 10^4, 99.8\%\) of eigenstates
\(\Delta t = 0.5\)
Divergence : L. Balents and M. P. A. Fisher, Phys. Rev. B 56, 12970 (1997)
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Bond disorder
\(L = 10^8\) sites
arXiv:2211.13089 (v1)
\(M = 10^4, 99.8\%\) of eigenstates
\(\Delta t = 0.5\)
Divergence : L. Balents and M. P. A. Fisher, Phys. Rev. B 56, 12970 (1997)
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Bond disorder
\(L = 10^8\) sites
arXiv:2211.13089 (v1)
\(M = 10^4, 99.8\%\) of eigenstates
\(\Delta t = 0.5\)
Divergence : L. Balents and M. P. A. Fisher, Phys. Rev. B 56, 12970 (1997)
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Bond disorder
\(L = 10^8\) sites
arXiv:2211.13089 (v1)
\(M = 10^4, 99.8\%\) of eigenstates
\(\Delta t = 0.5\)
Divergence : L. Balents and M. P. A. Fisher, Phys. Rev. B 56, 12970 (1997)
Evolution of localized wavefunctions
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Long-time limit
Strong disorder, \(L = 10^9\)
\(t \in [9.500, 10.500]\)
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Long-time limit
Strong disorder, \(L = 10^9\)
\(t \in [9.500, 10.500]\)
arXiv:2211.13089 (v1)
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Long-time limit
Strong disorder, \(L = 10^9\)
\(t \in [9.500, 10.500]\)
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Long-time limit
Strong disorder, \(L = 10^9\)
\(t \in [9.500, 10.500]\)
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\(L= 10^6\)
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\(L= 10^6\)
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Long-time limit
\(L= 10^6\)
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Weak disorder,
\(L = 10^8\)
Box, \(V = 0.05\)
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Weak disorder,
\(L = 10^8\)
Box, \(V = 0.05\)
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