Search for theHdibaryon on the lattice

Abstract

We investigate the H-dibaryon, an IðJ P Þ ¼ 0ð0 þ Þ with s ¼ À2, in the chiral and continuum regimes on anisotropic lattices in quenched QCD. Simulations are performed on modest lattices with refined techniques to obtain results with high accuracy over a spatial lattice spacing in the range of a s $ 0:19-0:40 fm. We present results for the energy difference between the ground state energy of the hexa-quark stranglet and the free two-baryon state from our ensembles. A negative energy shift observed in the chirally extrapolated results leads to the conclusion that the measured hexa-quark state is bound. This is further confirmed by the attractive interaction in the continuum limit with the observed H-dibaryon bound by 47 AE 37 MeV.

Probing unification scenarios with atomic clocks

“…And example of this type of analysis is Luo et al (2011) and we have recently updated this using newer data (Ferreira et al 2012). In what follows we summarise these results.…”

“…In particular, for an atomic clock of an alkali-like element, that frequency is the hyperfine frequency of the element-which depends, again, on several quantities ( (Luo et al 2011) (2) where R in f is the Rydberg constant, A h f s is a numerical factor depending on the atomic species, g i = 2µ i /µ N is the gyromagnetic factor (µ i being nuclear magnetic moment and µ N = e/2m p the nuclear magneton), α is the fine structure constant, µ ≡ m p m e is the protonto-electron mass ratio and F h f s (α) accounts for relativistic corrections.…”

“…Given the theoretical uncertainty, there are two possible approaches to relate the various parameters, further discussed in Luo et al (2011). In a simple shell model:…”

“…We will follow the approach of Coc et al (2007) and Luo et al (2011), considering a class of grand unification models in which the weak scale is determined by dimensional transmutation, and assuming that relative variation of all the Yukawa couplings is the same. As in Campbell & Olive (1995), we assume that the variation of the couplings is driven by a dilation-type scalar field.…”

Rabi oscillations, decoherence, and disentanglement in a qubit–spin-bath system

“…A more realistic type of environment takes the form of quantum interacting spin chains [3,[30][31][32][33][34][35], where the decay of the qubit's coherence is found to be related to the critical properties of the spin environments. Most prior work making use of such an environment considered qubit-spin bath coupling of the Ising form, which is spin conserving.…”