The Wilkinson Microwave Anisotropy Probe (WMAP) 5-year data provide stringent limits on deviations from the minimal, six-parameter Λ cold dark matter model. We report these limits and use them to constrain the physics of cosmic inflation via Gaussianity, adiabaticity, the power spectrum of primordial fluctuations, gravitational waves, and spatial curvature. We also constrain models of dark energy via its equation of state, parity-violating interaction, and neutrino properties, such as mass and the number of species. We detect no convincing deviations from the minimal model. The six parameters and the corresponding 68% uncertainties, derived from the WMAP data combined with the distance measurements from the Type Ia supernovae (SN) and the Baryon Acoustic Oscillations (BAO) in the distribution of galaxies, are: Ω b h 2 = 0.02267+0.00058 –0.00059, Ω c h 2 = 0.1131 ± 0.0034, ΩΛ = 0.726 ± 0.015, ns = 0.960 ± 0.013, τ = 0.084 ± 0.016, and at k = 0.002 Mpc-1. From these, we derive σ8 = 0.812 ± 0.026, H 0 = 70.5 ± 1.3 km s-1 Mpc–1, Ω b = 0.0456 ± 0.0015, Ω c = 0.228 ± 0.013, Ω m h 2 = 0.1358+0.0037 –0.0036, z reion = 10.9 ± 1.4, and t 0 = 13.72 ± 0.12 Gyr. With the WMAP data combined with BAO and SN, we find the limit on the tensor-to-scalar ratio of r 1 is disfavored even when gravitational waves are included, which constrains the models of inflation that can produce significant gravitational waves, such as chaotic or power-law inflation models, or a blue spectrum, such as hybrid inflation models. We obtain tight, simultaneous limits on the (constant) equation of state of dark energy and the spatial curvature of the universe: –0.14 < 1 + w < 0.12(95%CL) and –0.0179 < Ω k < 0.0081(95%CL). We provide a set of WMAP distance priors, to test a variety of dark energy models with spatial curvature. We test a time-dependent w with a present value constrained as –0.33 < 1 + w 0 < 0.21 (95% CL). Temperature and dark matter fluctuations are found to obey the adiabatic relation to within 8.9% and 2.1% for the axion-type and curvaton-type dark matter, respectively. The power spectra of TB and EB correlations constrain a parity-violating interaction, which rotates the polarization angle and converts E to B. The polarization angle could not be rotated more than –59 < Δα < 24 (95% CL) between the decoupling and the present epoch. We find the limit on the total mass of massive neutrinos of ∑m ν < 0.67 eV(95%CL), which is free from the uncertainty in the normalization of the large-scale structure data. The number of relativistic degrees of freedom (dof), expressed in units of the effective number of neutrino species, is constrained as N eff = 4.4 ± 1.5 (68%), consistent with the standard value of 3.04. Finally, quantitative limits on physically-motivated primordial non-Gaussianity parameters are –9 < f local NL < 111 (95% CL) and –151 < f equil NL < 253 (95% CL) for the local and equilateral models, respectively.

https://iopscience.iop.org/article/10.1088/0067-0049/180/2/330/pdf

Five-year wilkinson microwave anisotropy probe observations: cosmological interpretation

Metal–Organic Frameworks for Separations

The density-matrix renormalization group method (DMRG) has established itself over the last decade as the leading method for the simulation of the statics and dynamics of one-dimensional strongly correlated quantum lattice systems. In the further development of the method, the realization that DMRG operates on a highly interesting class of quantum states, so-called matrix product states (MPS), has allowed a much deeper understanding of the inner structure of the DMRG method, its further potential and its limitations. In this paper, I want to give a detailed exposition of current DMRG thinking in the MPS language in order to make the advisable implementation of the family of DMRG algorithms in exclusively MPS terms transparent. I then move on to discuss some directions of potentially fruitful further algorithmic development: while DMRG is a very mature method by now, I still see potential for further improvements, as exemplified by a number of recently introduced algorithms.

/pdf/the-density-matrix-renormalization-group-in-the-age-of-6718dr7b3l.pdf

The density-matrix renormalization group in the age of matrix product states

The density-matrix renormalization group (DMRG) is a numerical algorithm for the efficient truncation of the Hilbert space of low-dimensional strongly correlated quantum systems based on a rather general decimation prescription. This algorithm has achieved unprecedented precision in the description of one-dimensional quantum systems. It has therefore quickly become the method of choice for numerical studies of such systems. Its applications to the calculation of static, dynamic, and thermodynamic quantities in these systems are reviewed here. The potential of DMRG applications in the fields of two-dimensional quantum systems, quantum chemistry, three-dimensional small grains, nuclear physics, equilibrium and nonequilibrium statistical physics, and time-dependent phenomena is also discussed. This review additionally considers the theoretical foundations of the method, examining its relationship to matrix-product states and the quantum information content of the density matrices generated by the DMRG.

http://www.physics.udel.edu/~bnikolic/QTTG/NOTES/DMRG/SCHOLLWOCK=RMP_dmrg.pdf

The density-matrix renormalization group

This paper describes the development study of the beam emission spectroscopy (BES) for the turbulent transport study in Heliotron J. Modification of the sightlines (10 × 4 for edge and 10 × 2 for edge) enables us to obtain 2-dimensional BES imaging. The cooling effect on the reduction in the electrical noise of avalanche photodiode (APD) assembly has been investigated using a refrigerant cooling system. When the temperature of the APD element has set to be -20 °C, the electrical noise can be reduced more than 50%. The measurement error of the phase difference in the case of low signal level has been tested by two light-emitting diode lamps. The APD cooling has an effect to improve the measurement error at the low signal level of APD.

Development of beam emission spectroscopy for turbulence transport study in Heliotron J

Summary form only given. The electronic structure of the one dimensional Hubbard model with a less than half filling is studied by the resonating Hartree-Fock (Res HF) method. As basic units of quantum fluctuations in the ground state of the model, we consider charged and neutral solitons (S/sup +/ and S/sup 0/) and polarons (P/sup +/) in the spin density wave (SDW). The HF ground state of the system is an S/sup +/ gas at small U's and is a P/sup +/ gas at large U's, where U is the on-site Coulomb repulsion. The defects make a lattice in the weak correlation and large defect density regime, while they can move almost freely in the strong correlation and small defect density regime. In the real ground state these defects perform quantum translational and breathing motions and convert each other via the process S/sup +/ + S/sup 0/ - P/sup +/. Employing this picture of quantum fluctuations, the Res HF wave function composed of only 6 Slater determinants can explain at most 98.6% (U/t = 2) and at least 82.2% (U/t = 8) of the exact correlation energy in the Hubbard ring with 16 sites and 14 electrons, where t is the transfer energy.

Quantum fluctuations in the one dimensional hubbard model with a less than half filling

Motivated by the stimulative NMR observations of field-induced level crossings in molecular antiferromagnetic rings, we construct a microscopic theory of the spin dynamics in single-crystalline Cr 8 F 8 pivalates. We reproduce the low-temperature 1 H NMR relaxation rate 1/ T 1 as a function of magnetic field, which is single-peaked as usual but double-peaked intriguingly around the first and second level crossings, respectively. It is not poor crystallization such as mosaicity and gemination, but combined efforts of weak intramolecular antisymmetric interactions and nonnegligible intermolecular couplings that should split 1/ T 1 peaks substantially.

Theoretical Scenario for the Proton NMR Observation of Field-Induced Level Crossings in a Single Crystal of [Cr8F8(piv)16]

Investigating quantum fluctuations in the ground states of S=1 quantum antiferromagnetic spin chains described by the bilinear-biquadratic Hamiltonian ℋ=∑i [Si·Si+1+β (Si·Si+1)2], we study a mechanism of the breakdown of the Haldane phase. Based on the valence-bond-solid structure, but replacing two links of them by triplet bonds (crackions), we construct a trial wave function which is singlet and translationally invariant, where the crackion-crackion distance is regarded as a variational parameter. At β 1/3, crackions come to be set free from their bound state with increase of β and the chain length. We point out that the breakdown of the Haldane phase with β approaching 1 can be attributed to the collapse of the bound state and the growth of a short-range repulsive interaction between crackions.

Shoji Yamamoto

Papers

Development of beam emission spectroscopy for turbulence transport study in Heliotron J

Quantum fluctuations in the one dimensional hubbard model with a less than half filling

Theoretical Scenario for the Proton NMR Observation of Field-Induced Level Crossings in a Single Crystal of [Cr8F8(piv)16]

Breakdown of the Spin-1 Haldane Phase Via Quantum Fluctuations

Effects of the electron-phonon interaction of the charge ordering in quasi-one-dimensional charge-transfer salts