486 research outputs found
Large N reduction for Chern-Simons theory on S^3
We study a matrix model which is obtained by dimensional reduction of
Chern-Simon theory on S^3 to zero dimension. We find that expanded around a
particular background consisting of multiple fuzzy spheres, it reproduces the
original theory on S^3 in the planar limit. This is viewed as a new type of the
large N reduction generalized to curved space.Comment: 4 pages, 2 figures, references added, typos correcte
Large N reduction on group manifolds
We show that the large N reduction holds on group manifolds. Large N field
theories defined on group manifolds are equivalent to some corresponding matrix
models. For instance, gauge theories on S^3 can be regularized in a gauge
invariant and SO(4) invariant manner.Comment: 21 pages, 4 figures, typos corrected, a reference adde
Experimental Realization of a Relativistic Harmonic Oscillator
We report the experimental study of a harmonic oscillator in the relativistic
regime. The oscillator is composed of Bose-condensed lithium atoms in the third
band of an optical lattice, which have an energy-momentum relation nearly
identical to that of a massive relativistic particle, with an effective mass
reduced below the bare value and a greatly reduced effective speed of light.
Imaging the shape of oscillator trajectories at velocities up to 98% of the
effective speed of light reveals a crossover from sinusoidal to nearly
photon-like propagation. The existence of a maximum velocity causes the
measured period of oscillations to increase with energy; our measurements
reveal beyond-leading-order contributions to this relativistic anharmonicity.
We observe an intrinsic relativistic dephasing of oscillator ensembles, and a
monopole oscillation with exactly the opposite phase of that predicted for
non-relativistic harmonic motion. All observed dynamics are in quantitative
agreement with longstanding but hitherto-untested relativistic predictions.Comment: 10 pages; 4 figure
Large-N reduction for N=2 quiver Chern-Simons theories on S^3 and localization in matrix models
We study reduced matrix models obtained by the dimensional reduction of N=2
quiver Chern-Simons theories on S^3 to zero dimension and show that if a
reduced model is expanded around a particular multiple fuzzy sphere background,
it becomes equivalent to the original theory on S^3 in the large-N limit. This
is regarded as a novel large-N reduction on a curved space S^3. We perform the
localization method to the reduced model and compute the free energy and the
vacuum expectation value of a BPS Wilson loop operator. In the large-N limit,
we find an exact agreement between these results and those in the original
theory on S^3.Comment: 46 pages, 11 figures; minor modification
Observation and uses of position-space Bloch oscillations in an ultracold gas
We report the direct observation and characterization of position-space Bloch
oscillations using an ultracold gas in a tilted optical lattice. While Bloch
oscillations in momentum space are a common feature of optical lattice
experiments, the real-space center-of-mass dynamics are typically too small to
resolve. Tuning into the regime of rapid tunneling and weak force, we observe
real-space Bloch oscillation amplitudes of hundreds of lattice sites, in both
ground and excited bands. We demonstrate two unique capabilities enabled by
tracking of Bloch dynamics in position space: measurement of the full
position-momentum phase-space evolution during a Bloch cycle, and direct
imaging of the lattice band structure. These techniques, along with the ability
to exert long-distance coherent control of quantum gases without modulation,
may open up new possibilities for quantum control and metrology.Comment: 5 pages, 6 figure
Quantifying and Controlling Prethermal Nonergodicity in Interacting Floquet Matter
The use of periodic driving for synthesizing many-body quantum states depends crucially on the existence of a prethermal regime, which exhibits drive-tunable properties while forestalling the effects of heating. This dependence motivates the search for direct experimental probes of the underlying localized nonergodic nature of the wave function in this metastable regime. We report experiments on a many-body Floquet system consisting of atoms in an optical lattice subjected to ultrastrong sign-changing amplitude modulation. Using a double-quench protocol, we measure an inverse participation ratio quantifying the degree of prethermal localization as a function of tunable drive parameters and interactions. We obtain a complete prethermal map of the drive-dependent properties of Floquet matter spanning four square decades of parameter space. Following the full time evolution, we observe sequential formation of two prethermal plateaux, interaction-driven ergodicity, and strongly frequency-dependent dynamics of long-time thermalization. The quantitative characterization of the prethermal Floquet matter realized in these experiments, along with the demonstration of control of its properties by variation of drive parameters and interactions, opens a new frontier for probing far-from-equilibrium quantum statistical mechanics and new possibilities for dynamical quantum engineering
Golgi apparatus casein kinase phosphorylates bioactive Ser-6 of bone morphogenetic protein 15 and growth and differentiation factor 9
AbstractBone morphogenetic protein-15 (BMP-15) and growth and differentiation factor-9 (GDF-9) are oocyte-secreted factors that play essential roles in human folliculogenesis and ovulation. Their bioactivity is tightly regulated through phosphorylation, likely to occur within the Golgi apparatus of the secretory pathway. Here we show that Golgi apparatus casein kinase (G-CK) catalyzes the phosphorylation of rhBMP-15 and rhGDF-9. rhBMP-15, in particular, is an excellent substrate for G-CK. In each protein a single residue is phosphorylated by G-CK, corresponding to the serine residue at the sixth position of the mature region of both rhBMP-15 and rhGDF-9, whose phosphorylation is required for biological activity
N=4 Super Yang-Mills from the Plane Wave Matrix Model
We propose a nonperturbative definition of N=4 super Yang-Mills (SYM). We
realize N=4 SYM on RxS^3 as the theory around a vacuum of the plane wave matrix
model. Our regularization preserves sixteen supersymmetries and the gauge
symmetry. We perform the 1-loop calculation to give evidences that the
superconformal symmetry is restored in the continuum limit.Comment: 39 pages, 6 figures, some sentences are improved, references added,
typos corrected, version to appear in PR
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