Alternative formalism to the slave particle mean field theory of the t-J model without deconfinement

An alternative formalism that does not require the assumption of the deconfinement phase of a U(1) gauge field is proposed for the slave particle mean field theory. Starting form the spin-fermion model, a spinon field, which is either fermion or boson, is introduced to represent the localized spin moment. We find a d-wave superconductive state in the mean field theory in the case of the fermion representation of the localized spin moment that corresponds to the slave boson mean field theory of the t-J model, whereas the d-wave superconductive state is absent in case of the Schwinger boson representation of the localized spin moments.Comment: 8 page

New Superconducting and Magnetic Phases Emerge on the Verge of Antiferromagnetism in CeIn3_3

We report the discovery of new superconducting and novel magnetic phases in CeIn$_3$ on the verge of antiferromagnetism (AFM) under pressure ($P$) through the In-nuclear quadrupole resonance (NQR) measurements. We have found a $P$-induced phase separation of AFM and paramagnetism (PM) without any trace for a quantum phase transition in CeIn$_3$. A new type of superconductivity (SC) was found in $P=2.28-2.5$ GPa to coexist with AFM that is magnetically separated from PM where the heavy fermion SC takes place. We propose that the magnetic excitations such as spin-density fluctuations induced by the first-order magnetic phase transition might mediate attractive interaction to form Cooper pairs.Comment: 4 pages, 4 EPS figures, submitted to J. Phys. Soc. Jp

Fully Off-shell Effective Action and its Supersymmetry in Matrix Theory

As a step toward clarification of the power of supersymmetry (SUSY) in Matrix theory, a complete calculation, including all the spin effects, is performed of the effective action of a probe D-particle, moving along an arbitrary trajectory in interaction with a large number of coincident source D-particles, at one loop at order 4 in the derivative expansion. Furthermore, exploiting the SUSY Ward identity developed previously, the quantum-corrected effective supersymmetry transformation laws are obtained explicitly to the relevant order and are used to verify the SUSY-invariance of the effective action. Assuming that the agreement with 11-dimensional supergravity persists, our result can be regarded as a prediction for supergravity calculation, which, yet unavailable, is known to be highly non-trivial.Comment: 27 page

Coherent matter waves emerging from Mott-insulators

We study the formation of (quasi-)coherent matter waves emerging from a Mott insulator for strongly interacting bosons on a one-dimensional lattice. It has been shown previously that a quasi-condensate emerges at momentum k=\pi/2a, where a is the lattice constant, in the limit of infinitely strong repulsion (hard-core bosons). Here we show that this phenomenon persists for all values of the repulsive interaction that lead to a Mott insulator at a commensurate filling. The non-equilibrium dynamics of hard-core bosons is treated exactly by means of a Jordan-Wigner transformation, and the generic case is studied using a time-dependent density matrix renormalization group technique. Different methods for controlling the emerging matter wave are discussed.Comment: 20 pages, 11 figures. Published versio

Quantum Monte Carlo simulations of infinitely strongly correlated fermions

Numerical simulations of the two-dimensional t-J model in the limit $J/t \ll 1$ are performed for rather large systems (up to $N = 12 \times 12$) using a world-line loop-algorithm. It is shown that in the one-hole case with J=0, where no minus signs appear, very low temperatures ($\beta t \sim 3000$) are necessary in order to reach Nagaoka's state. J/t \ltsim 0.05 leads to the formation of partially polarized systems, whereas J/t \gtsim 0.05 corresponds to minimal spin. The two-hole case shows enhanced total spin up to the lowest attainable temperatures ($\beta t = 150$).Comment: 6 pages, 5 figure

Oral health status: relationship to nutrient and food intake among 80‐year‐old Japanese adults

Objectives The aim of this cross‐sectional study was to investigate the relationship of oral health status defined on the basis of presence of posterior occluding pairs ( POP s) and adequacy of removable denture fit as determined by self‐report to nutrient and food intake among older Japanese. Methods The subjects were 353 Japanese aged 80 years in 2008 and were classified into four groups according to the number of POP s, defined as pairs of occluding natural, restored, or fixed prosthetic postcanine teeth (range: 0–8) and removable denture status. The groups were: (i) good dentition ( n  =   56; 8 POP s and no removable prosthesis), (ii) well‐fitting dentures ( n  =   158; <8 POP s with self‐reported good‐fitting dentures), (iii) ill‐fitting dentures ( n  =   70; <8 POP s with self‐reported ill‐fitting dentures), and (iv) compromised dentition ( n  =   69; <8 POP s and no removable prosthesis). Multivariable analysis of the differences in nutrient and food intake outcome variables which were collected via validated food frequency questionnaire among the four oral health status groups was conducted using general linear models. Results Intake of multiple nutrients was significantly ( P  <   0.05) lower in the group with ill‐fitting dentures or compromised dentition than in the good dentition group. Vegetable, fish, and shellfish consumption was significantly lower in the ill‐fitting dentures or compromised dentition groups. No significant differences were seen in dietary intake between the well‐fitting dentures and good dentition groups. Conclusions Dietary intake was poorer in those with self‐perceived ill‐fitting dentures or fewer POP s than among those having all POP s. Regular dental care to maintain intact dentition, as well as dental treatment to replace missing teeth and ensure adequate denture fit and function, may be important to the diet intake and subsequent nutritional status of older Japanese.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/108691/1/cdoe12100.pd