660 research outputs found
Quantum Robots Plus Environments
A quantum robot is a mobile quantum system including an on bord quantum
computer and ancillary systems, that interact with an environment of quantum
systems. Quantum robots carry out tasks whose goals include carrying out
measurements and physical experiments on the environment. Environments
considered so far in the literature: oracles, data bases, and quantum
registers, are shown to be special cases of environments considered here. It is
noted that quantum robots should include a quantum computer and cannot be
simply a multistate head. A model is discussed in which each task, as a
sequence of computation and action phases, is described by a unitary step
operator. Overall system dynamics is described in terms of a Feynman sum over
paths of completed computation and action phases. A simple task example,
measuring the distance between the quantum robot and a particle on a 1D space
lattice, with quantum phase path and time duration dispersion present, is
analyzed.Comment: 10 pages Latex, 1 postscript figur
New Gauge Fields from Extension of Parallel Transport of Vector Spaces to Underlying Scalar Fields
Gauge theories can be described by assigning a vector space V(x) to each
space time point x. A common set of complex numbers, C, is usually assumed to
be the set of scalars for all the V{x}. This is expanded here to assign a
separate set of scalars, C{x}, to V{x} for each x. The freedom of choice of
bases, expressed by the action of a gauge group operator on the V{x}, is
expanded here to include the freedom of choice of complex scale factors,
c_{y,x}, as elements of GL(1,C) that relate C{y} to C{x}. A gauge field
representation of c_{y,x} gives two gauge fields, A(x) and iB(x). Inclusion of
these fields in the covariant derivatives of Lagrangians results in A(x)
appearing as a gauge boson for which mass is optional and B(x) as a massless
gauge boson. B(x) appears to be the photon field. The nature of A(x) is not
known at present. One does know that the coupling constant of A(x) to matter
fields is very small compared to the fine structure constant.Comment: 16 pages,1 figure, paper for talk at SPIE conference, April 27-29,
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Quantum Robots and Quantum Computers
Validation of a presumably universal theory, such as quantum mechanics,
requires a quantum mechanical description of systems that carry out theoretical
calculations and experiments. The description of quantum computers is under
active development. No description of systems to carry out experiments has been
given. A small step in this direction is taken here by giving a description of
quantum robots as mobile systems with on board quantum computers that interact
with environments. Some properties of these systems are discussed. A specific
model based on the literature descriptions of quantum Turing machines is
presented.Comment: 18 pages, RevTex, one postscript figure. Paper considerably revised
and enlarged. submitted to Phys. Rev.
The Representation of Numbers by States in Quantum Mechanics
The representation of numbers by tensor product states of composite quantum
systems is examined. Consideration is limited to k-ary representations of
length L and arithmetic modulo k^{L}. An abstract representation on an L fold
tensor product Hilbert space H^{arith} of number states and operators for the
basic arithmetic operations is described. Unitary maps onto a physical
parameter based tensor product space H^{phy} are defined and the relations
between these two spaces and the dependence of algorithm dynamics on the
unitary maps is discussed. The important condition of efficient implementation
by physically realizable Hamiltonians of the basic arithmetic operations is
also discussed.Comment: Paper, 8 pages, for Proceedings, QCM&C 3, O Hirota and P. Tombesi,
Editors, Kluver/Plenum, publisher
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