The ground state energy of the ±J spin glass from the genetic algorithm

1994 ◽  
Vol 4 (9) ◽  
pp. 1281-1285 ◽  
Author(s):  
P. Sutton ◽  
D. L. Hunter ◽  
N. Jan
1999 ◽  
Vol 10 (07) ◽  
pp. 1327-1333
Author(s):  
COLIN CHISHOLM ◽  
MARK LUKEMAN ◽  
N. JAN ◽  
D. L. HUNTER

We measure the "inherent structures" of the ±J Ising spin glass in four dimensions (4D) and find a behavior similar to that seen for the 2D and 3D systems. We are able to determine the transition temperature from the overlap between the quenched states and the equilibrium states. We find that the transition temperature Tsg is 2.07±0.05 which agrees well with the recently reported value of 2.03±0.03 by Maranari and Zuliani. We also find that the ground state energy for the 4D spin glass is near -2.087±0.005, a more precise estimate than the value of -1.83 reported earlier.


1996 ◽  
Vol 99 (4) ◽  
pp. 247-248 ◽  
Author(s):  
T. Wanschura ◽  
D.A. Coley ◽  
S. Migowsky

Author(s):  
Wei-Kuo Chen ◽  
Arnab Sen

Abstract For $p\geq 1$ and $(g_{ij})_{1\leq i,j\leq n}$ being a matrix of i.i.d. standard Gaussian entries, we study the $n$-limit of the $\ell _p$-Gaussian–Grothendieck problem defined as $$\begin{align*} & \max\Bigl\{\sum_{i,j=1}^n g_{ij}x_ix_j: x\in \mathbb{R}^n,\sum_{i=1}^n |x_i|^p=1\Bigr\}. \end{align*}$$The case $p=2$ corresponds to the top eigenvalue of the Gaussian orthogonal ensemble; when $p=\infty $, the maximum value is essentially the ground state energy of the Sherrington–Kirkpatrick mean-field spin glass model and its limit can be expressed by the famous Parisi formula. In the present work, we focus on the cases $1\leq p<2$ and $2<p<\infty .$ For the former, we compute the limit of the $\ell _p$-Gaussian–Grothendieck problem and investigate the structure of the set of all near optimizers along with stability estimates. In the latter case, we show that this problem admits a Parisi-type variational representation and the corresponding optimizer is weakly delocalized in the sense that its entries vanish uniformly in a polynomial order of $n^{-1}$.


2009 ◽  
Vol 9 (7&8) ◽  
pp. 701-720
Author(s):  
N. Bansal ◽  
S. Bravyi ◽  
B.M. Terhal

We describe a classical approximation algorithm for evaluating the ground state energy of the classical Ising Hamiltonian with linear terms on an arbitrary planar graph. The running time of the algorithm grows linearly with the number of spins and exponentially with $1/\epsilon$, where $\epsilon$ is the worst-case relative error. This result contrasts the well known fact that exact computation of the ground state energy for the two-dimensional Ising spin glass model is NP-hard. We also present a classical approximation algorithm for the quantum Local Hamiltonian Problem or Quantum Ising Spin Glass problem on a planar graph {\em with bounded degree} which is known to be a QMA-complete problem. Using a different technique we find a classical approximation algorithm for the quantum Ising spin glass problem on the simplest planar graph with unbounded degree, the star graph.


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