332,512 research outputs found
The group of causal automorphisms
The group of causal automorphisms on Minkowski space-time is given and its
structure is analyzed
QCD Sum Rule for S_{11}(1535)
We propose a new interpolating field for S(1535) to determine its mass
from QCD sum rules. In the nonrelativistic limit, this interpolating field
dominantly reduces to two quarks in the s-wave state and one quark in the
p-wave state. An optimization procedure, which makes use of a duality relation,
yields the interpolating field which overlaps strongly with the negative-parity
baryon and at the same time does not couple at all to the low lying
positive-parity baryon. Using this interpolating field and applying the
conventional QCD sum rule analysis, we find that the mass of S is
reasonably close to the experimentally known value, even though the precise
determination depends on the poorly known quark-gluon condensate. Hence our
interpolating field can be used to investigate the spectral properties of
S(1535).Comment: 12 pages, Revtex, 1 ps figure available from author
3D local qupit quantum code without string logical operator
Recently Haah introduced a new quantum error correcting code embedded on a
cubic lattice. One of the defining properties of this code is the absence of
string logical operator. We present new codes with similar properties by
relaxing the condition on the local particle dimension. The resulting code is
well-defined when the local Hilbert space dimension is prime. These codes can
be divided into two different classes: the local stabilizer generators are
either symmetric or antisymmetric with respect to the inversion operation.
These is a nontrivial correspondence between these two classes. For any
symmetric code without string logical operator, there exists a complementary
antisymmetric code with the same property and vice versa. We derive a
sufficient condition for the absence of string logical operator in terms of the
algebraic constraints on the defining parameters of the code. Minimal number of
local particle dimension which satisfies the condition is 5. These codes have
logarithmic energy barrier for any logical error.Comment: 9 pages, 7 figure
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