2,110 research outputs found
Recommended from our members
Intrinsic bidirectional dynamic nuclear polarization by optically pumped trions in quantum dots
This paper has been updated by the author to: arXiv:1012.0060v1
[cond-mat.mes-hall], titled "Collective Nuclear Stabilization by Optically
Excited Hole in Quantum Dot
Quantum measurement of hyperfine interaction in nitrogen-vacancy center
We propose an efficient quantum measurement protocol for the hyperfine
interaction between the electron spin and the N nuclear spin of a
diamond nitrogen-vacancy center. In this protocol, a sequence of quantum
operations of successively increasing duration is utilized to estimate the
hyperfine interaction with successively higher precision approaching the
quantum metrology limit. This protocol does not need the preparation of the
nuclear spin state. In the presence of realistic operation errors and electron
spin decoherence, the overall precision of our protocol still surpasses the
standard quantum limit
The last of the simple remainders
This article is distributed under the terms of the Creative Commons
Attribution License (CC-BY 4.0), which permits any use, distribution and reproduction in
any medium, provided the original author(s) and source are credited
The Grassmannian and the Twistor String: Connecting All Trees in N=4 SYM
We present a new, explicit formula for all tree-level amplitudes in N=4 super
Yang-Mills. The formula is written as a certain contour integral of the
connected prescription of Witten's twistor string, expressed in link variables.
A very simple deformation of the integrand gives directly the Grassmannian
integrand proposed by Arkani-Hamed et al. together with the explicit contour of
integration. The integral is derived by iteratively adding particles to the
Grassmannian integral, one particle at a time, and makes manifest both parity
and soft limits. The formula is shown to be related to those given by Dolan and
Goddard, and generalizes the results of earlier work for NMHV and N^2MHV to all
N^(k-2)MHV tree amplitudes in N=4 super Yang-Mills.Comment: 26 page
A time-domain control signal detection technique for OFDM
Transmission of system-critical control information plays a key role in efficient management of limited wireless network resources and successful reception of payload data information. This paper uses an orthogonal frequency division multiplexing (OFDM) architecture to investigate the detection performance of a time-domain approach used to detect deterministic control signalling information. It considers a type of control information chosen from a finite set of information, which is known at both transmitting and receiving wireless terminals. Unlike the maximum likelihood (ML) estimation method, which is often used, the time-domain detection technique requires no channel estimation and no pilots as it uses a form of time-domain correlation as the means of detection. Results show that when compared with the ML method, the time-domain approach improves detection performance even in the presence of synchronisation error caused by carrier frequency offset
Expression of testicular genes in haematological malignancies
The gene expression of a new group of tumour antigens known as cancer/testis (CT) antigens is now well-recognized in some solid tumours. However, their expression in haematological malignancies remained unclear. In this study, we have used reverse transcription polymerase chain reaction and Southern blot analysis to examine the presence of transcripts for the three CT antigens, NY-ESO-1, SSX2 and SCP1 in haematological malignant cells. We found that transcripts for SCP1 could be detected in 10% of myeloma, 5.7% of acute myeloid leukaemia and 23% of chronic myeloid leukaemia. In contrast, NY-ESO-1 and SSX2 were not detected in any of the 107 tumour samples. © 1999 Cancer Research Campaig
A Shift Symmetry in the Higgs Sector: Experimental Hints and Stringy Realizations
We interpret reported hints of a Standard Model Higgs boson at ~ 125 GeV in
terms of high-scale supersymmetry breaking with a shift symmetry in the Higgs
sector. More specifically, the Higgs mass range suggested by recent LHC data
extrapolates, within the (non-supersymmetric) Standard Model, to a vanishing
quartic Higgs coupling at a UV scale between 10^6 and 10^18 GeV. Such a small
value of lambda can be understood in terms of models with high-scale SUSY
breaking if the Kahler potential possesses a shift symmetry, i.e., if it
depends on H_u and H_d only in the combination (H_u+\bar{H}_d). This symmetry
is known to arise rather naturally in certain heterotic compactifications. We
suggest that such a structure of the Higgs Kahler potential is common in a
wider class of string constructions, including intersecting D7- and D6-brane
models and their extensions to F-theory or M-theory. The latest LHC data may
thus be interpreted as hinting to a particular class of compactifications which
possess this shift symmetry.Comment: v2: References added. v3: References added, published versio
Fermionic response from fractionalization in an insulating two-dimensional magnet
Conventionally ordered magnets possess bosonic elementary excitations, called
magnons. By contrast, no magnetic insulators in more than one dimension are
known whose excitations are not bosons but fermions. Theoretically, some
quantum spin liquids (QSLs) -- new topological phases which can occur when
quantum fluctuations preclude an ordered state -- are known to exhibit Majorana
fermions as quasiparticles arising from fractionalization of spins. Alas,
despite much searching, their experimental observation remains elusive. Here,
we show that fermionic excitations are remarkably directly evident in
experimental Raman scattering data across a broad energy and temperature range
in the two-dimensional material -RuCl. This shows the importance of
magnetic materials as hosts of Majorana fermions. In turn, this first
systematic evaluation of the dynamics of a QSL at finite temperature emphasizes
the role of excited states for detecting such exotic properties associated with
otherwise hard-to-identify topological QSLs.Comment: 5 pages, 3 figure
Narrowband Biphotons: Generation, Manipulation, and Applications
In this chapter, we review recent advances in generating narrowband biphotons
with long coherence time using spontaneous parametric interaction in monolithic
cavity with cluster effect as well as in cold atoms with electromagnetically
induced transparency. Engineering and manipulating the temporal waveforms of
these long biphotons provide efficient means for controlling light-matter
quantum interaction at the single-photon level. We also review recent
experiments using temporally long biphotons and single photons.Comment: to appear as a book chapter in a compilation "Engineering the
Atom-Photon Interaction" published by Springer in 2015, edited by A.
Predojevic and M. W. Mitchel
- …