Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Simulating Strongly Correlated Quantum Systems with Tree Tensor Networks   We present a tree-tensor-network-based method to study strongly correlated
systems with nonlocal interactions in higher dimensions. Although the
momentum-space and quantum-chemistry versions of the density matrix
renormalization group (DMRG) method have long been applied to such systems, the
spatial topology of DMRG-based methods allows efficient optimizations to be
carried out with respect to one spatial dimension only. Extending the
matrix-product-state picture, we formulate a more general approach by allowing
the local sites to be coupled to more than two neighboring auxiliary subspaces.
Following Shi. et. al. [Phys. Rev. A, 74, 022320 (2006)], we treat a tree-like
network ansatz with arbitrary coordination number z, where the z=2 case
corresponds to the one-dimensional scheme. For this ansatz, the long-range
correlation deviates from the mean-field value polynomially with distance, in
contrast to the matrix-product ansatz, which deviates exponentially. The
computational cost of the tree-tensor-network method is significantly smaller
than that of previous DMRG-based attempts, which renormalize several blocks
into a single block. In addition, we investigate the effect of unitary
transformations on the local basis states and present a method for optimizing
such transformations. For the 1-d interacting spinless fermion model, the
optimized transformation interpolates smoothly between real space and momentum
space. Calculations carried out on small quantum chemical systems support our
approach.

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The categories of this paper are: atom-ph
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The categories of this paper are: mtrl-th
18
The categories of this paper are: econ
22
The categories of this paper are: chao-dyn
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The categories of this paper are: eess
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The categories of this paper are: nlin
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The categories of this paper are: gr-qc
3
The categories of this paper are: physics
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The categories of this paper are: alg-geom
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The categories of this paper are: adap-org
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The categories of this paper are: funct-an
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The categories of this paper are: hep-th
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The categories of this paper are: patt-sol
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The categories of this paper are: q-alg
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The categories of this paper are: chem-ph
2
The categories of this paper are: math