3 research outputs found
Loneliness among Homeless Individuals during the First Wave of the COVID-19 Pandemic.
The feeling of loneliness is a major public health concern associated with multiple somatic and psychiatric illnesses. Studies have shown increasing incidence of loneliness in the general population during the first wave of the COVID-19 pandemic. Homeless individuals are a particularly vulnerable group; however, little is known about loneliness among homeless individuals. We therefore aimed to examine the prevalence of loneliness among homeless individuals during the pandemic. Furthermore, we estimated the association between loneliness and sociodemographic and lifestyle factors, as well as the self-perceived risk of contracting COVID-19. Data from the Hamburg survey of homeless individuals were used, including 151 homeless individuals that were recruited in spring of 2020. Loneliness was measured by the 3- item version of the UCLA-3 Loneliness Scale. To summarize, 48.5% of the participants experienced loneliness. Multiple linear regressions showed increased loneliness to be associated with male gender (β = 1.07, p = 0.01), being single (β = 1.33, p = 0.00), originating from Germany (β = 1.48, p = 0.00), high frequency of sharing a sleeping space with more than three people (β = 0.42, p = 0.02) and a higher self-perceived risk of contracting COVID-19 (β = 0.41, p = 0.02). On the contrary, there was no association of loneliness with age, educational level, chronic alcohol consumption or frequently sharing a sleeping space. In conclusion, the magnitude of loneliness among homeless individuals during the pandemic was highlighted. Description of factors determining loneliness may help to identify homeless individuals at risk
A quantum energy inequality in the Sine--Gordon model
We consider the stress tensor in the massless Sine--Gordon model in the
finite regime of the theory. We prove convergence of the
renormalised perturbative series for the interacting stress tensor defined
using the Bogoliubov formula in an arbitrary Hadamard state, even for the case
that the smearing is only along a one-dimensional time-like worldline and not
in space-time. We then show that the interacting energy density, as seen by an
observer following this worldline, satisfies an absolute lower bound, that is a
bound independent of the quantum state. Our proof employs and generalises
existing techniques developed for free theories by Flanagan, Fewster and Smith.Comment: 42 pages in CMP style, expanded introduction/acknowledgements, new
reference
Local operators in the Sine-Gordon model: and the stress tensor
We consider the simplest non-trivial local composite operators in the
massless Sine-Gordon model, which are
and the stress tensor . We show that even in the finite regime
of the theory, these operators need additional
renormalisation (beyond the free-field normal-ordering) at each order in
perturbation theory. We further prove convergence of the renormalised
perturbative series for their expectation values, both in the Euclidean
signature and in Minkowski space-time, and for the latter in an arbitrary
Hadamard state. Lastly, we show that one must add a quantum correction
(proportional to ) to the renormalised stress tensor to obtain a
conserved quantity.Comment: 57 pages in CMP styl