Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Fast Universal Quantum Computation with Railroad-switch Local
  Hamiltonians   We present two universal models of quantum computation with a
time-independent, frustration-free Hamiltonian. The first construction uses
3-local (qubit) projectors, and the second one requires only 2-local
qubit-qutrit projectors. We build on Feynman's Hamiltonian computer idea and
use a railroad-switch type clock register. The resources required to simulate a
quantum circuit with L gates in this model are O(L) small-dimensional quantum
systems (qubits or qutrits), a time-independent Hamiltonian composed of O(L)
local, constant norm, projector terms, the possibility to prepare computational
basis product states, a running time O(L log^2 L), and the possibility to
measure a few qubits in the computational basis. Our models also give a
simplified proof of the universality of 3-local Adiabatic Quantum Computation.

9
The categories of this paper are: nlin
3
The categories of this paper are: physics
32
The categories of this paper are: atom-ph
12
The categories of this paper are: nucl-th
28
The categories of this paper are: alg-geom
10
The categories of this paper are: q-bio
27
The categories of this paper are: comp-gas
31
The categories of this paper are: ao-sci
30
The categories of this paper are: q-alg
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The categories of this paper are: solv-int
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The categories of this paper are: adap-org
33
The categories of this paper are: plasm-ph
25
The categories of this paper are: patt-sol
0
The categories of this paper are: hep-ph
22
The categories of this paper are: chao-dyn
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The categories of this paper are: hep-ex