Symplectic N and time reversal in frustrated magnetism

Identifying the time reversal symmetry of spins as a symplectic symmetry, we develop a large N approximation for quantum magnetism that embraces both antiferromagnetism and ferromagnetism. In SU(N), N>2, not all spins invert under time reversal, so we have introduced a new large N treatment which builds interactions exclusively out of the symplectic subgroup [SP(N)] of time reversing spins, a more stringent condition than the symplectic symmetry of previous SP(N) large N treatments. As a result, we obtain a mean field theory that incorporates the energy cost of frustrated bonds. When applied to the frustrated square lattice, the ferromagnetic bonds restore the frustration dependence of the critical spin in the Neel phase, and recover the correct frustration dependence of the finite temperature Ising transition.Comment: added reference

Weight stigma in frequent exercisers: Overt, demeaning and condescending.

The aim of this study was to qualitatively examine weight stigma in individuals who exercise frequently. In total, six focus groups, comprising 30 participants aged 18-25 years, were conducted using convenience sampling. All participants were frequent exercisers. Five themes emerged in the data with participants discussing bullying, the consequences of obesity, causes of obesity, lack of willpower and interventions to reduce obesity. This study is the first qualitative examination of weight stigmatisation in frequent exercisers, where the beliefs reported by focus group participants suggest that frequent exercisers stigmatise, discriminate and dehumanise obese people. Future research to examine the impact of weight stigma on exercise motivation and behaviour of obese people appears warranted