530 research outputs found
Role of Swirl in Flame Stabilization
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/90697/1/AIAA-2011-108-333.pd
Quantum Metropolis Sampling
The original motivation to build a quantum computer came from Feynman who
envisaged a machine capable of simulating generic quantum mechanical systems, a
task that is believed to be intractable for classical computers. Such a machine
would have a wide range of applications in the simulation of many-body quantum
physics, including condensed matter physics, chemistry, and high energy
physics. Part of Feynman's challenge was met by Lloyd who showed how to
approximately decompose the time-evolution operator of interacting quantum
particles into a short sequence of elementary gates, suitable for operation on
a quantum computer. However, this left open the problem of how to simulate the
equilibrium and static properties of quantum systems. This requires the
preparation of ground and Gibbs states on a quantum computer. For classical
systems, this problem is solved by the ubiquitous Metropolis algorithm, a
method that basically acquired a monopoly for the simulation of interacting
particles. Here, we demonstrate how to implement a quantum version of the
Metropolis algorithm on a quantum computer. This algorithm permits to sample
directly from the eigenstates of the Hamiltonian and thus evades the sign
problem present in classical simulations. A small scale implementation of this
algorithm can already be achieved with today's technologyComment: revised versio
Unsteady Aspects of Lean Premixed Prevaporized Gas Turbine Combustors: Flame-Flame Interactions
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/90643/1/AIAA-54144-606.pd
Computation of the coefficients appearing in the uniform asymptotic expansions of integrals
The coefficients that appear in uniform asymptotic expansions for integrals
are typically very complicated. In the existing literature the majority of the
work only give the first two coefficients. In a limited number of papers where
more coefficients are given the evaluation of the coefficients near the
coalescence points is normally highly numerically unstable. In this paper, we
illustrate how well-known Cauchy type integral representations can be used to
compute the coefficients in a very stable and efficient manner. We discuss the
cases: (i) two coalescing saddles, (ii) two saddles coalesce with two branch
points, (iii) a saddle point near an endpoint of the interval of integration.
As a special case of (ii) we give a new uniform asymptotic expansion for Jacobi
polynomials in terms of Laguerre polynomials
as that holds uniformly for near .
Several numerical illustrations are included.Comment: 18 page
Experimental Investigation of Premixed Turbulent Combustion in High Reynolds Number Regimes using PLIF
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/140710/1/6.2014-0314.pd
Sequential Strong Measurements and Heat Vision
We study scenarios where a finite set of non-demolition von-Neumann
measurements are available. We note that, in some situations, repeated
application of such measurements allows estimating an infinite number of
parameters of the initial quantum state, and illustrate the point with a
physical example. We then move on to study how the system under observation is
perturbed after several rounds of projective measurements. While in the finite
dimensional case the effect of this perturbation always saturates, there are
some instances of infinite dimensional systems where such a perturbation is
accumulative, and the act of retrieving information about the system increases
its energy indefinitely (i.e., we have `Heat Vision'). We analyze this effect
and discuss a specific physical system with two dichotomic von-Neumann
measurements where Heat Vision is expected to show.Comment: See the Appendix for weird examples of heat visio
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