12,554 research outputs found
Multiple time scale blinking in InAs quantum dot single-photon sources
We use photon correlation measurements to study blinking in single,
epitaxially-grown self-assembled InAs quantum dots situated in circular Bragg
grating and microdisk cavities. The normalized second-order correlation
function g(2)(\tau) is studied across eleven orders of magnitude in time, and
shows signatures of blinking over timescales ranging from tens of nanoseconds
to tens of milliseconds. The g(2)(\tau) data is fit to a multi-level system
rate equation model that includes multiple non-radiating (dark) states, from
which radiative quantum yields significantly less than 1 are obtained. This
behavior is observed even in situations for which a direct histogramming
analysis of the emission time-trace data produces inconclusive results
A biological sequence comparison algorithm using quantum computers
Genetic information is encoded in a linear sequence of nucleotides,
represented by letters ranging from thousands to billions. Mutations refer to
changes in the DNA or RNA nucleotide sequence. Thus, mutation detection is
vital in all areas of biology and medicine. Careful monitoring of
virulence-enhancing mutations is essential. However, an enormous amount of
classical computing power is required to analyze genetic sequences of this
size. Inspired by human perception of vision and pixel representation of images
on quantum computers, we leverage these techniques to implement a pairwise
sequence analysis. The methodology has a potential advantage over classical
approaches and can be further applied to identify mutations and other
modifications in genetic sequences. We present a method to display and analyze
the similarity between two genome sequences on a quantum computer where a
similarity score is calculated to determine the similarity between nucleotides.Comment: 14 pages, 8 figures, 3 tables New version: typo in figure 7 New
version because of a missing information in affiliations in footer, page
The Renormalization Group in Nuclear Physics
Modern techniques of the renormalization group (RG) combined with effective
field theory (EFT) methods are revolutionizing nuclear many-body physics. In
these lectures we will explore the motivation for RG in low-energy nuclear
systems and its implementation in systems ranging from the deuteron to neutron
stars, both formally and in practice. Flow equation approaches applied to
Hamiltonians both in free space and in the medium will be emphasized. This is a
conceptually simple technique to transform interactions to more perturbative
and universal forms. An unavoidable complication for nuclear systems from both
the EFT and flow equation perspective is the need to treat many-body forces and
operators, so we will consider these aspects in some detail. We'll finish with
a survey of current developments and open problems in nuclear RG.Comment: 37 pages; 49th Schladming Theoretical Physics Winter School lecture
notes; to appear in Nucl. Phys. B Proc. Suppl. (2012
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