5,511 research outputs found
Environmental exposures and mutational patterns of cancer genomes
The etiology of most human cancers is unknown. Genetic inheritance and environmental factors are thought to have major roles, and for some types of cancer, exposure to carcinogens is a proven mechanism leading to tumorigenesis. Sequencing of entire cancer genomes has not only begun to provide clues regarding functionally relevant mutations, but has also paved the way towards understanding the initial exposures leading to DNA damage, repair and eventually to mutation of specific sequences within a cancer genome. Two recent studies of melanoma and small cell lung cancer exemplify what type of information can be gained from cancer genome sequencing
Ideal Bose gas in fractal dimensions and superfluid He in porous media
Physical properties of ideal Bose gas with the fractal dimensionality between
D=2 and D=3 are theoretically investigated. Calculation shows that the
characteristic features of the specific heat and the superfluid density of
ideal Bose gas in fractal dimensions are strikingly similar to those of
superfluid Helium-4 in porous media. This result indicates that the geometrical
factor is dominant over mutual interactions in determining physical properties
of Helium-4 in porous media.Comment: 13 pages, 6 figure
Muon accelerators -- Muon lifetime measurements as window to Planck scale physics
A prominent effective description of particles interacting with the quantum
properties of gravity is through modifications of the general relativistic
dispersion relation. Such modified dispersion relations lead to modifications
in the relativistic time dilation. A perfect probe for this effect, which goes
with the particle energy cubed over the quantum gravity scale
and the square of the particle mass would be a very light
unstable particle for which one can detect the lifetime in the laboratory as a
function of its energy to very high precision. In this article we conjecture
that a muon collider or accelerator would be a perfect tool to investigate the
existence of an anomalous time dilation, and with it the fundamental structure
of spacetime at the Planck scale.Comment: 12 pages, 2 figures. Matches version published in Classical and
Quantum Gravity Focus Issue: "Focus on Quantum Gravity Phenomenology in the
Multi-Messenger Era: Challenges and Perspectives
Numerical study of multilayer adsorption on fractal surfaces
We report a numerical study of van der Waals adsoprtion and capillary
condensation effects on self-similar fractal surfaces. An assembly of uncoupled
spherical pores with a power-law distributin of radii is used to model fractal
surfaces with adjustable dimensions. We find that the commonly used fractal
Frankel-Halsey-Hill equation systematically fails to give the correct dimension
due to crossover effects, consistent with the findings of recent experiments.
The effects of pore coupling and curvature dependent surface tension were also
studied.Comment: 11 pages, 3 figure
Entanglement renormalization, scale invariance, and quantum criticality
The use of entanglement renormalization in the presence of scale invariance
is investigated. We explain how to compute an accurate approximation of the
critical ground state of a lattice model, and how to evaluate local
observables, correlators and critical exponents. Our results unveil a precise
connection between the multi-scale entanglement renormalization ansatz (MERA)
and conformal field theory (CFT). Given a critical Hamiltonian on the lattice,
this connection can be exploited to extract most of the conformal data of the
CFT that describes the model in the continuum limit.Comment: 4 pages, 3 figures, RevTeX 4. Revised for greater clarit
Simulation of anyons with tensor network algorithms
Interacting systems of anyons pose a unique challenge to condensed matter
simulations due to their non-trivial exchange statistics. These systems are of
great interest as they have the potential for robust universal quantum
computation, but numerical tools for studying them are as yet limited. We show
how existing tensor network algorithms may be adapted for use with systems of
anyons, and demonstrate this process for the 1-D Multi-scale Entanglement
Renormalisation Ansatz (MERA). We apply the MERA to infinite chains of
interacting Fibonacci anyons, computing their scaling dimensions and local
scaling operators. The scaling dimensions obtained are seen to be in agreement
with conformal field theory. The techniques developed are applicable to any
tensor network algorithm, and the ability to adapt these ansaetze for use on
anyonic systems opens the door for numerical simulation of large systems of
free and interacting anyons in one and two dimensions.Comment: Fixed typos, matches published version. 16 pages, 21 figures, 4
tables, RevTeX 4-1. For a related work, see arXiv:1006.247
Boundary quantum critical phenomena with entanglement renormalization
We extend the formalism of entanglement renormalization to the study of
boundary critical phenomena. The multi-scale entanglement renormalization
ansatz (MERA), in its scale invariant version, offers a very compact
approximation to quantum critical ground states. Here we show that, by adding a
boundary to the scale invariant MERA, an accurate approximation to the critical
ground state of an infinite chain with a boundary is obtained, from which one
can extract boundary scaling operators and their scaling dimensions. Our
construction, valid for arbitrary critical systems, produces an effective chain
with explicit separation of energy scales that relates to Wilson's RG
formulation of the Kondo problem. We test the approach by studying the quantum
critical Ising model with free and fixed boundary conditions.Comment: 8 pages, 12 figures, for a related work see arXiv:0912.289
First order wetting of rough substrates and quantum unbinding
Replica and functional renormalization group methods show that, with short
range substrate forces or in strong fluctuation regimes, wetting of a
self-affine rough wall in 2D turns first-order as soon as the wall roughness
exponent exceeds the anisotropy index of bulk interface fluctuations. Different
thresholds apply with long range forces in mean field regimes. For
bond-disordered bulk, fixed point stability suggests similar results, which
ultimately rely on basic properties of quantum bound states with asymptotically
power-law repulsive potentials.Comment: 11 pages, 1 figur
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