119173091
Order in a Spatially Anisotropic Triangular Antiferromagnet
The phase diagram of the spin-1/2 Heisenberg antiferromagnet on an anisotropic triangular lattice of weakly coupled chains is investigated using a renormalization group analysis which includes marginal couplings important for connecting to numerical studies of this model. In particular, the relative stability of incommensurate spiral spin density order and collinear antiferromagnetic order is studied. While incommensurate spiral order is found to exist over most of the phase diagram in the presence of a Dzyaloshinskii-Moriya (DM) interaction, at small interchain coupling and extremely weak DM coupling, collinear antiferromagnetic order can survive. The implications of the renormalization group analysis for numerical studies, many of which have found spin liquid-like behaviour, are discussed.
118483089
Holographic description of large N gauge theory
Abstract Based on the earlier work [S.-S. Lee, Nucl. Rev. B 832 (2010) 567], we derive a holographic dual for the D -dimensional U ( N ) lattice gauge theory from a first principle construction. The resulting theory is a lattice field theory of closed loops, dubbed as lattice loop field theory which is defined on a ( D + 1 ) -dimensional space. The lattice loop field theory is well defined non-perturbatively, and it becomes weakly coupled and local in the large N limit with a large ʼt Hooft coupling.
119218989
Holographic description of quantum field theory
Abstract We propose that general D-dimensional quantum field theories are dual to ( D + 1 ) -dimensional local quantum theories which in general include objects with spin two or higher. Using a general prescription, we construct a ( D + 1 ) -dimensional theory which is holographically dual to the D-dimensional O ( N ) vector model. From the holographic theory, the phase transition and critical properties of the model in dimensions D > 2 are described.
118620419
Background independent holographic description: from matrix field theory to quantum gravity
A bstractWe propose a local renormalization group procedure where length scale is changed in spacetime dependent way. Combining this scheme with an earlier observation that high energy modes in renormalization group play the role of dynamical sources for low energy modes at each scale, we provide a prescription to derive background independent holographic duals for field theories. From a first principle construction, it is shown that the holographic theory dual to a D-dimensional matrix field theory is a (D + 1)-dimensional quantum theory of gravity coupled with matter fields of various spins. The gravitational theory has (D + 1) first-class constraints which generate local spacetime transformations in the bulk. The (D + 1)-dimensional diffeomorphism invariance is a consequence of the freedom to choose different local RG schemes.
4971151
Quantum renormalization group and holography
A bstractQuantum renormalization group scheme provides a microscopic understanding of holography through a general mapping between the beta functions of underlying quantum field theories and the holographic actions in the bulk. We show that the Einstein gravity emerges as a holographic description upto two derivative order for a matrix field theory which has no other operator with finite scaling dimension except for the energymomentum tensor. We also point out that holographic actions for general large N matrix field theories respect the inversion symmetry along the radial direction in the bulk if the beta functions of single-trace operators are gradient flows with respect to the target space metric set by the beta functions of double-trace operators.
118451455
Non-Fermi liquid from a charged black hole: A critical Fermi ball
Using the anti-de Sitter/conformal field theory correspondence, we calculate a fermionic spectral function in a 2+1 dimensional nonrelativistic quantum field theory which is dual to a gravitational theory in the AdS{sub 4} background with a charged black hole. The spectral function shows no quasiparticle peak but the Fermi surface is still well-defined. Interestingly, all momentum points inside the Fermi surface are critical and the gapless modes are defined in a critical Fermi ball in the momentum space.
118671237
Overlapping resonances and chaos in halo formation
The ‘‘particle‐core’’ model in the framework of Kapchinskij‐Vladimirskij (KV) distribution function approach is used in order to study dynamics of a test particle in a space charge dominated beam propagating through time‐dependent FOFO focusing channel. A simple analytical method is suggested in order to find a closed orbit solution for the envelope; the question about stability of small amplitude oscillations of weakly mismatched beam around the closed orbit solution is considered. The test particle motion is described by the methods of Hamiltonian dynamics; it is shown that a set of parametric resonances of the particle Hamiltonian can be generated by mismatched envelope oscillations in the time‐dependent focusing channel. It is demonstrated that the onset of global chaos in the particle phase space exhibits a sharp transition when the amplitude of envelope oscillations is larger than some critical value. Implications caused by the time dependence of the linear focusing field are discussed. The relation...
120385865
Is the momentum space optimally used with the FODO lattices
The available momentum space of a FODO lattice is determined by the maximum value of the dispersion function (δx=Dx ∂p/p). In a regular FODO lattice the dispersion function oscillates between its maximum and minimum values, which are always positive. The maximum value of the dispersion function in a FODO cell of a fixed length depends on the cell phase difference. An example of a new lattice, in which the dispersion function is lowered to half its value in the same FODO cell, is presented. The available momentum space in the new lattice is raised to twice that in the FODO lattice by allowing the dispersion function to oscillate between the same positive and negative values. The maxima of the dispersion function in the new lattice have half the value of those within the regular 90° cells.
32583309
Beam property measurements in the IUCF cooler ring
The high intensity stored beam stability limits of the IUCF (Indiana University Cyclotron Facility) cooler-storage ring are being explored. Measurements of the equilibrium emittance and bunching factor for a 45 MeV electron cooled proton beam as a function of stored beam intensity are reported. In addition, calculations of space-charge tune shift based on these measurements are presented. The tune shift is found to be as large as about 0.3 in magnitude, depending on the degree to which the beam is cooled. The space-charge tune shift is discussed as a possible contributing factor to observed stored beam current limits.<<ETX>>
125510730
Experimental beam dynamics at the third integer resonance
The nonlinear beam dynamics of transverse betatron oscillations have been studied experimentally at the IUCF Cooler Ring. Motion in one dimension was measured for betatron tunes near the third integer resonance. The Hamiltonian for nonlinear particle motion near the third integer resonance has been experimentally deduced and is compared with the results from a simple model.
55331667
The evolution of tensor polarization
Using the equation of motion for the vector polarization, the spin transfer matrix for spin tensor polarization is derived. We study the evolution equation for the tensor polarization in the presence of an isolated spin resonance and in the presence of a spin rotator, or snake.<<ETX>>