155 research outputs found
Huyghens, Bohr, Riemann and Galois: Phase-Locking
Several mathematical views of phase-locking are developed. The classical
Huyghens approach is generalized to include all harmonic and subharmonic
resonances and is found to be connected to 1/f noise and prime number theory.
Two types of quantum phase-locking operators are defined, one acting on the
rational numbers, the other on the elements of a Galois field. In both cases we
analyse in detail the phase properties and find them related respectively to
the Riemann zeta function and to incomplete Gauss sums.Comment: 18 pages paper written in relation to the ICSSUR'05 conference held
in Besancon, France to be published at a special issue of IJMP
Three-qubit entangled embeddings of CPT and Dirac groups within E8 Weyl group
In quantum information context, the groups generated by Pauli spin matrices,
and Dirac gamma matrices, are known as the single qubit Pauli group P, and
two-qubit Pauli group P2, respectively. It has been found [M. Socolovsky, Int.
J. Theor. Phys. 43, 1941 (2004)] that the CPT group of the Dirac equation is
isomorphic to P. One introduces a two-qubit entangling orthogonal matrix S
basically related to the CPT symmetry. With the aid of the two-qubit swap gate,
the S matrix allows the generation of the three-qubit real Clifford group and,
with the aid of the Toffoli gate, the Weyl group W(E8) is generated (M. Planat,
Preprint 0904.3691). In this paper, one derives three-qubit entangling groups ?
P and ? P2, isomorphic to the CPT group P and to the Dirac group P2, that are
embedded into W(E8). One discovers a new class of pure theequbit quantum states
with no-vanishing concurrence and three-tangle that we name CPT states. States
of the GHZ and CPT families, and also chain-type states, encode the new
representation of the Dirac group and its CPT subgroup.Comment: 12 page
Fast high fidelity quantum non-demolition qubit readout via a non-perturbative cross-Kerr coupling
Qubit readout is an indispensable element of any quantum information
processor. In this work, we experimentally demonstrate a non-perturbative
cross-Kerr coupling between a transmon and a polariton mode which enables an
improved quantum non-demolition (QND) readout for superconducting qubits. The
new mechanism uses the same experimental techniques as the standard QND qubit
readout in the dispersive approximation, but due to its non-perturbative
nature, it maximizes the speed, the single-shot fidelity and the QND properties
of the readout. In addition, it minimizes the effect of unwanted decay channels
such as the Purcell effect. We observed a single-shot readout fidelity of 97.4%
for short 50 ns pulses, and we quantified a QND-ness of 99% for long
measurement pulses with repeated single-shot readouts
Spontaneous Cardiomyocyte Differentiation From Adipose Tissue Stroma Cells
Cardiomyocyte regeneration is limited in adult life. Thus, the identification of a putative source of cardiomyocyte progenitors is of great interest to provide a usable model in vitro and new perspective in regenerative therapy. As adipose tissues were recently demonstrated to contain pluripotent stem cells, the emergence of cardiomyocyte phenotype from adipose-derived cells was investigated. We demonstrated that rare beating cells with cardiomyocyte features could be identified after culture of adipose stroma cells without addition of 5-azacytidine. The cardiomyocyte phenotype was first identified by morphological observation, confirmed with expression of specific cardiac markers, immunocytochemistry staining, and ultrastructural analysis, revealing the presence of ventricle- and atrial-like cells. Electrophysiological studies performed on early culture revealed a pacemaker activity of the cells. Finally, functional studies showed that adrenergic agonist stimulated the beating rate whereas cholinergic agonist decreased it. Taken together, this study demonstrated that functional cardiomyocyte- like cells could be directly obtained from adipose tissue. According to the large amount of this tissue in adult mammal, it could represent a useful source of cardiomyocyte progenitors.Garcia Verdugo, Jose Manuel, [email protected]
Hjelmslev Geometry of Mutually Unbiased Bases
The basic combinatorial properties of a complete set of mutually unbiased
bases (MUBs) of a q-dimensional Hilbert space H\_q, q = p^r with p being a
prime and r a positive integer, are shown to be qualitatively mimicked by the
configuration of points lying on a proper conic in a projective Hjelmslev plane
defined over a Galois ring of characteristic p^2 and rank r. The q vectors of a
basis of H\_q correspond to the q points of a (so-called) neighbour class and
the q+1 MUBs answer to the total number of (pairwise disjoint) neighbour
classes on the conic.Comment: 4 pages, 1 figure; extended list of references, figure made more
illustrative and in colour; v3 - one more figure and section added, paper
made easier to follow, references update
Qubit readout using in-situ bifurcation of a nonlinear dissipative polariton in the mesoscopic regime
We explore the nonlinear response to a strong drive of polaritonic meters for
superconducting qubit state readout. The two polaritonic meters result from the
strong hybridization between a bosonic mode of a 3D microwave cavity and an
anharmonic ancilla mode of the superconducting circuit. Both polaritons inherit
a self-Kerr nonlinearity , and decay rate from the ancilla and
cavity, respectively. They are coupled to a transmon qubit via a
non-perturbative cross-Kerr coupling resulting in a large cavity pull . By applying magnitic flux, the ancilla mode frequency varies
modifying the hybridization conditions and thus the properties of the readout
polariton modes. Using this, the hybridisation is tuned in the mesoscopic
regime of the non-linear dissipative polariton where the self-Kerr and decay
rates of one polariton are similar leading to bistability and
bifurcation behavior at small photon number. This bistability and bifurcation
behavior depends on the qubit state and we report qubit state readout in a
latching-like manner thanks to the bifurcation of the upper polariton. Without
any external quantum-limited amplifier, we obtain a single-shot fidelity of
in a ns integration time
Human adipose derived stroma/stem cells grow in serum-free medium as floating spheres,â
With the goal of obtaining clinically safe human adipose-derived stroma/stem cells (ASC) and eliminating the use of serum, we have developed a new culture system that allows the expansion of ASC as spheres in a defined medium. These spheres can be passaged several times. They are not only aggregated cells but rather originate from single cells as clonal spheres can be obtained after seeding at very low density and reform clonal spheres after dissociation. These spheres can also revert to monolayer growth when plated in medium containing human plasma and even generate fibroblast-like colonies (CFU-f). Under several differentiation-specific media, spheresderived ASC maintain their capacity to differentiate into osteoblasts, endothelial cells and adipocytes. These results indicate that human ASC can be maintained in a serum-free 3D culture system, which is of great interest for the expansion in bioreactors of autologous ASC and their use in clinical trials
State preparation of a fluxonium qubit with feedback from a custom FPGA-based platform
We developed a versatile integrated control and readout instrument for
experiments with superconducting quantum bits (qubits), based on a
field-programmable gate array (FPGA) platform. Using this platform, we perform
measurement-based, closed-loop feedback operations with
platform latency. The feedback capability is instrumental in realizing active
reset initialization of the qubit into the ground state in a time much shorter
than its energy relaxation time . We show experimental results
demonstrating reset of a fluxonium qubit with fidelity, using a
readout-and-drive pulse sequence approximately long.
Compared to passive ground state initialization through thermalization, with
the time constant given by , the use of the
FPGA-based platform allows us to improve both the fidelity and the time of the
qubit initialization by an order of magnitude.Comment: 3 pages, 2 figures. The following article has been submitted to the
AIP Conference Proceedings of the Fifth International Conference on Quantum
Technologies (ICQT-2019
Stromal Vascular Fraction Transplantation as an Alternative Therapy for Ischemic Heart Failure: Anti-inflammatory Role
<p>Abstract</p> <p>Background</p> <p>The aims of this study were: (1) to show the feasibility of using adipose-derived stromal vascular fraction (SVF) as an alternative to bone marrow mono nuclear cell (BM-MNC) for cell transplantation into chronic ischemic myocardium; and (2) to explore underlying mechanisms with focus on anti-inflammation role of engrafted SVF and BM-MNC post chronic myocardial infarction (MI) against left ventricular (LV) remodelling and cardiac dysfunction.</p> <p>Methods</p> <p>Four weeks after left anterior descending coronary artery ligation, 32 Male Lewis rats with moderate MI were divided into 3 groups. SVF group (n = 12) had SVF cell transplantation (6 à 10<sup>6 </sup>cells). BM-MNC group (n = 12) received BM-MNCs (6 à 10<sup>6</sup>) and the control (n = 10) had culture medium. At 4 weeks, after the final echocardiography, histological sections were stained with Styrus red and immunohistochemical staining was performed for α-smooth muscle actin, von Willebrand factor, CD3, CD8 and CD20.</p> <p>Results</p> <p>At 4 weeks, in SVF and BM-MNC groups, LV diastolic dimension and LV systolic dimension were smaller and fractional shortening was increased in echocardiography, compared to control group. Histology revealed highest vascular density, CD3+ and CD20+ cells in SVF transplanted group. SVF transplantation decreased myocardial mRNA expression of inflammatory cytokines TNF-α, IL-6, MMP-1, TIMP-1 and inhibited collagen deposition.</p> <p>Conclusions</p> <p>Transplantation of adipose derived SVF cells might be a useful therapeutic option for angiogenesis in chronic ischemic heart disease. Anti-inflammation role for SVF and BM transplantation might partly benefit for the cardioprotective effect for chronic ischemic myocardium.</p
Bases for qudits from a nonstandard approach to SU(2)
Bases of finite-dimensional Hilbert spaces (in dimension d) of relevance for
quantum information and quantum computation are constructed from angular
momentum theory and su(2) Lie algebraic methods. We report on a formula for
deriving in one step the (1+p)p qupits (i.e., qudits with d = p a prime
integer) of a complete set of 1+p mutually unbiased bases in C^p. Repeated
application of the formula can be used for generating mutually unbiased bases
in C^d with d = p^e (e > or = 2) a power of a prime integer. A connection
between mutually unbiased bases and the unitary group SU(d) is briefly
discussed in the case d = p^e.Comment: From a talk presented at the 13th International Conference on
Symmetry Methods in Physics (Dubna, Russia, 6-9 July 2009) organized in
memory of Prof. Yurii Fedorovich Smirnov by the Bogoliubov Laboratory of
Theoretical Physics of the JINR and the ICAS at Yerevan State University
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