7,834 research outputs found
Thermal Green Functions in Coordinate Space for Massless Particles of any Spin
The thermal Wightman functions for free, massless particles of spin 0, 1/2,
1, 3/2, and 2 are computed directly in coordinate space by solving the
appropriate differential equation and imposing the Kubo-Martin-Schwinger
condition. The solutions are valid for real, imaginary, or complex time. The
Wightman functions for spin 1 gauge bosons and for spin 2 gravitons are
directly related to the fundamental functions for spin 0. The Wightman
functions for spin 3/2 gravitinos is directly related to that for spin 1/2
fermions. Calculations for spin 1, 3/2, and 2 are done in covariant gauges. In
the deep space-like region the Wightman functions for bosons fall like
whereas those for the fermions fall exponentially. In the deep time-like region
all the Wightman functions fall exponentially.Comment: 8 pages, RevTex twocolum
From modern workplaces to modern families – re-envisioning the work–family conflict
The Modern Workplaces Consultation 2011 set the foundations for the current revisions to work–family rights in the UK. They are underpinned by a desire to make modern workplaces more flexible and responsive to the needs of working families. The Children and Families Act 2014 implements, in part, the consultation’s proposals, but falls far short of its most significant recommendations. Nevertheless, it does extend access to work–family rights to some alternative working family models. The analysis undertaken here, however, indicates that this is limited to families that most closely conform to the dual-partnered working family model. Drawing from Fineman, Herring and McGlynn’s references to relationships of care, it is argued that instead of re-branding current rights the government should re-envision the concept of the family and family care. It is only through renegotiating the categories of caregiving recognised in law that the needs of modern working families will genuinely be met
Photon Radiation in a Heat Bath
We discuss the bremsstrahlung of photons into a heat bath, and calculate from
first principles the energy radiated. Even to lowest order the spectrum of the
radiation at low frequency is no more singular than at zero temperature. In
addition to the obvious contributions, this spectrum includes terms associated
with fluctuations. [Revised version has additional explanations]Comment: 7 pages, plus 2 figures in pictex DAMTP 94/
Propagation of Majorana fermions in hot plasma
The properties of Majorana fermions in hot plasma are studied. One-loop
resummed propagator, dispersion relations and their interpretation are
discussed. It is shown that particle and hole -like solutions appear as in
Dirac/chiral fermion case. The dispersion relations are, however, crucially
different. We find that, in presence of a large zero temperature bare mass,
hole -like excitations posses a negligible effective mass. As an example of
real application, we consider the neutralinos in the minimal supersymmetric
extension of the standard model and argue that for realistic values of the soft
supersymmetry breaking masses the existence of practically massless hole -like
excitations have a considerable effect on the thermal properties, e.g. the
thermalization rate, of particles interacting with these Majorana excitations.Comment: 9 pages + 2 figsures, LaTe
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