3,535 research outputs found
No saturation of the quantum Bogomolnyi bound by two-dimensional supersymmetric solitons
We reanalyse the question whether the quantum Bogomolnyi bound is saturated
in the two-dimensional supersymmetric kink and sine-Gordon models. Our starting
point is the usual expression for the one-loop correction to the mass of a
soliton in terms of sums over zero-point energies. To regulate these sums, most
authors put the system in a box with suitable boundary conditions, and impose
an ultraviolet cut-off. We distinguish between an energy cut-off and a mode
number cut-off, and show that they lead to different results. We claim that
only the mode cut-off yields correct results, and only if one considers exactly
the same number of bosonic and fermionic modes in the total sum over
bound-state and zero-point energies. To substantiate this claim, we show that
in the sine-Gordon model only the mode cut-off yields a result for the quantum
soliton mass that is consistent with the exact result for the spectrum as
obtained by Dashen et al. from quantising the so-called breather solution. In
the supersymmetric case, our conclusion is that contrary to previous claims the
quantum Bogomolnyi bound is not saturated in any of the two-dimensional models
considered.Comment: 23 pages, LATe
IRMM HCB and HCBD in Blankvoorn (testmaterial for reference material)
Blankvoorn Nieuwe Merwede (Roach, Rutilus rultilus) has been tested as a reference material for the components HCBD and HCB for biota monitoring according to the Water Framework Directive. Both components in the blankvoorn are present at moderate levels (overall average levels of respectively HCBD 1.6 μg/kg and HCB 6.2 μg/kg). These concentrations are far above reporting limits (respectively 0.1 μg/kg for HCBD and 0.2 μg/kg for HCB) and should therefore be suitable for use in a reference material
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