1,095 research outputs found
Experimental demonstration of Shor's algorithm with quantum entanglement
Shor's powerful quantum algorithm for factoring represents a major challenge
in quantum computation and its full realization will have a large impact on
modern cryptography. Here we implement a compiled version of Shor's algorithm
in a photonic system using single photons and employing the non-linearity
induced by measurement. For the first time we demonstrate the core processes,
coherent control, and resultant entangled states that are required in a
full-scale implementation of Shor's algorithm. Demonstration of these processes
is a necessary step on the path towards a full implementation of Shor's
algorithm and scalable quantum computing. Our results highlight that the
performance of a quantum algorithm is not the same as performance of the
underlying quantum circuit, and stress the importance of developing techniques
for characterising quantum algorithms.Comment: 4 pages, 5 figures + half-page additional online materia
Manipulating biphotonic qutrits
Quantum information carriers with higher dimension than the canonical qubit
offer significant advantages. However, manipulating such systems is extremely
difficult. We show how measurement induced non-linearities can be employed to
dramatically extend the range of possible transforms on biphotonic qutrits; the
three level quantum systems formed by the polarisation of two photons in the
same spatio-temporal mode. We fully characterise the biphoton-photon
entanglement that underpins our technique, thereby realising the first instance
of qubit-qutrit entanglement. We discuss an extension of our technique to
generate qutrit-qutrit entanglement and to manipulate any bosonic encoding of
quantum information.Comment: 4 pages, 4 figure
Dynamics of Resonances in Strongly Interacting Systems
The effects of the propagation of particles which have a finite life-time and
an according broad distribution in their mass spectrum are discussed in the
context of a transport descriptions. In the first part some example cases of
mesonic modes in nuclear matter at finite densities and temperatures are
presented. These equilibrium calculations illustrate the dynamical range of
spectral distributions to be adequately covered by non-equilibrium description
of the dynamics of two nuclei colliding at high energies. The second part
addresses the problem of transport descriptions which properly account for the
damping width of the particles. A systematic and general gradient approximation
is presented in the form of diagrammatic rules which permit to derive a
self-consistent transport scheme from the Kadanoff--Baym equation. The scheme
is conserving and thermodynamically consistent provided the self-energies are
obtained within the Phi-derivable two-particle irreducible (2PI) method of
Baym. The merits, the limitations and partial cures of the limitations of this
transport scheme are discussed in detail.Comment: To appear in the proceedings of the International Conference
"Progress in Nonequilibrium Green's Functions III", Kiel, 22.-26. August 200
Chemical composition and bioactivity of essential oils and extracts from Oregano from Madeira Island, Portugal
In the course of ongoing investigations on polymorphic Lamiaceae species, we
studied Origanum vulgare spp. virens growing wild in several locations of Madeira
Island, Portugal. Variation in essential oil composition with climate conditions was
studied. The antimicrobial activity of the various essential oils was determined
against 10 strains of bacteria and yeasts, usually found as human pathogenic or food
contaminants. The essential oils inhibited all the bacteria tested excepting for P.
aeruginosa. The most sensitive microorganism was M. smegmatis with MIC = 25 µg
ml-1 for two of the oils. The results of this study suggest a potential application of
these oils in preventing the human pathogenic and food contaminant
microorganisms growth. Radical scavenging capacity of essential oils and solvent
extract (hexane, chloroform, ethyl acetate and methanol) were also determined,
since interest of oregano resides in both non polar and polar fractions, all known by
their very high antioxidant activity. From the hexane fraction, we obtained a large
amount of 1-hexacosanol, C26H54O, a long chain alcohol, which was previously
extracted in the non-esterified form only from Hygrophila erecta.info:eu-repo/semantics/publishedVersio
Lack of hydroxylation-induced migration with 4-iodophenylalanine
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/32730/1/0000098.pd
Black Hole Thermodynamics in Horava Lifshitz Gravity and the Related Geometry
Recently, Hoava proposed a non-relativistic renormalizable theory
of gravity which is essentially a field theoretic model for a UV complete
theory of gravity and reduces to Einstein gravity with a non-vanishing
cosmological constant in IR. Also the theory admits a Lifshitz scale-invariance
in time and space with broken Lorentz symmetry at short scale. On the other
hand, at large distances higher derivative terms do not contribute and the
theory coincides with general relativity. Subsequently, Cai and his
collaborators and then Catiuo et al have obtained black hole solutions in this
gravity theory and studied the thermodynamic properties of the black hole
solution. In the present paper, we have investigated the black hole
thermodynamic for two choices of the entropy function - a classical and a
topological in nature. Finally, it is examined whether a phase transition is
possible or not.Comment: 8 figure
Static and dynamic single leg postural control performance during dual-task paradigms
ABSTRACTCombining dynamic postural control assessments and cognitive tasks may give clinicians a more accurate indication of postural control under sport-like conditions compared to single-task assessments. We examined postural control, cognitive and squatting performance of healthy individuals during static and dynamic postural control assessments in single- and dual-task paradigms. Thirty participants (female = 22, male = 8; age = 20.8 ± 1.6 years, height = 157.9 ± 13.0 cm, mass = 67.8 ± 20.6 kg) completed single-leg stance and single-leg squat assessments on a force plate individually (single-task) and concurrently (dual-task) with two cognitive assessments, a modified Stroop test and the Brooks Spatial Memory Test. Outcomes included centre of pressure speed, 95% confidence ellipse, squat depth and speed and cognitive test measures (percentage of correct answers and reaction time). Postural control performance varied between postural control assessments and testing paradigms. Participants did not squat..
Production of resonances in a thermal model: invariant-mass spectra and balance functions
We present a calculation of the pi+ pi- invariant-mass correlations and the
pion balance functions in the single-freeze-out model. A satisfactory agreement
with the data for Au+Au collisions is found.Comment: Contribution to QM 2004 (4 pages, 2 figures
Optogalvanic Spectroscopy of Metastable States in Yb^{+}
The metastable ^{2}F_{7/2} and ^{2}D_{3/2} states of Yb^{+} are of interest
for applications in metrology and quantum information and also act as dark
states in laser cooling. These metastable states are commonly repumped to the
ground state via the 638.6 nm ^{2}F_{7/2} -- ^{1}D[5/2]_{5/2} and 935.2 nm
^{2}D_{3/2} -- ^{3}D[3/2]_{1/2} transitions. We have performed optogalvanic
spectroscopy of these transitions in Yb^{+} ions generated in a discharge. We
measure the pressure broadening coefficient for the 638.6 nm transition to be
70 \pm 10 MHz mbar^{-1}. We place an upper bound of 375 MHz/nucleon on the
638.6 nm isotope splitting and show that our observations are consistent with
theory for the hyperfine splitting. Our measurements of the 935.2 nm transition
extend those made by Sugiyama et al, showing well-resolved isotope and
hyperfine splitting. We obtain high signal to noise, sufficient for laser
stabilisation applications.Comment: 8 pages, 5 figure
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