Chiral perturbation theory with Wilson-type fermions including a2a^2 effects: Nf=2N_f=2 degenerate case

We have derived the quark mass dependence of $m_{\pi}^2$, $m_{\rm AWI}$ and $f_{\pi}$, using the chiral perturbation theory which includes the $a^2$ effect associated with the explicit chiral symmetry breaking of the Wilson-type fermions, in the case of the $N_f=2$ degenerate quarks. Distinct features of the results are (1) the additive renormalization for the mass parameter $m_q$ in the Lagrangian, (2) $O(a)$ corrections to the chiral log ($m_q\log m_q$) term, (3) the existence of more singular term, $\log m_q$, generated by $a^2$ contributions, and (4) the existence of both $m_q\log m_q$ and $\log m_q$ terms in the quark mass from the axial Ward-Takahashi identity, $m_{\rm AWI}$. By fitting the mass dependence of $m_\pi^2$ and $m_{\rm AWI}$, obtained by the CP-PACS collaboration for $N_f=2$ full QCD simulations, we have found that the data are consistently described by the derived formulae. Resumming the most singular terms $\log m_q$, we have also derived the modified formulae, which show a better control over the next-to-leading order correction.Comment: 21 pages, 4 figures (10 eps files), Revtex4, some discussions and references added, the final version to appear in PR

B Physics with NRQCD: A Quenched Study

We present results on the spectrum of B mesons and heavy baryons, using a non-relativistic formulation for the heavy and a clover action for the light quark. We also discuss B meson decay constants and their dependency upon the heavy meson mass.Comment: 4 pages, uuencoded compressed postscript file, contribution to LATTICE 9

Remedial Adaptations in Building Services to Reduce COVID-19 Transmission

The work presented in this paper is aimed at assessing the various remedial building services engineering measures that can be applied to enable safer building occupation during the ongoing (at the time of writing) COVID-19 pandemic, as well as additional resilience in the event of similar events in the future. Due to the rapid development of research into the SARS-CoV-2 virus and COVID- 19, new data is becoming available on an ongoing basis. The available information at the time of writing has been appraised and conclusions have made based on the most prevalent scientific theories. Guidance from various building services engineering bodies have been assessed for the UK (CIBSE), Europe (RHEVA) and the USA (ASHRAE) as well as governmental guidance/mandates in the UK and abroad. This paper assesses the potential effectiveness of each measure at reducing the transmission of COVID-19; the ease of application within existing building services systems; the negative connotations for energy-usage, utility costs, carbon emissions and system maintenance/lifespan; and any adverse implications for the comfort of occupants. The investigated measures will then be appraised for their effectiveness at combatting the spread of COVID-19 compared with the ease of which they can be implemented (in terms of practicality and financial viability)

Squeezed states: A geometric framework

A general definition of squeezed states is proposed and its main features are illustrated through a discussion of the standard optical coherent states represented by 'Gaussian pure states'. The set-up involves representations of groups on Hilbert spaces over homogeneous spaces of the group, and relies on the construction of a square integrable (coherent state) group representation modulo a subgroup. This construction depends upon a choice of a Borel section which has a certain permissible arbitrariness in its selection; this freedom is attributable to a squeezing of the defining coherent states of the representation, and corresponds in this way to a sort of gauging

Bound on Hardy's non-locality from the principle of Information Causality

Recently,the principle of nonviolation of information causality [Nature 461,1101 (2009)], has been proposed as one of the foundational properties of nature. We explore the Hardy's nonlocality theorem for two qubit systems, in the context of generalised probability theory, restricted by the principle of nonviolation of information causality. Applying, a sufficient condition for information causality violation, we derive an upper bound on the maximum success probability of Hardy's nonlocality argument. We find that the bound achieved here is higher than that allowed by quantum mechanics,but still much less than what the nosignaling condition permits. We also study the Cabello type nonlocality argument (a generalization of Hardy's argument) in this context.Comment: Abstract modified, changes made in the conclusion, throughout the paper we clarified that the condition used by us is protocal based and is only a sufficient condition for the violation of information causalit

Hardy's argument and successive spin-s measurements

We consider a hidden-variable theoretic description of successive measurements of non commuting spin observables on a input spin-s state. In this scenario, the hidden-variable theory leads to a Hardy-type argument that quantum predictions violate it. We show that the maximum probability of success of Hardy's argument in quantum theory is $(\frac{1}{2})^{4s}$, which is more than in the spatial case.Comment: 7 page

Heavy-light meson decay constants from NRQCD: an analysis of the 1/M corrections

We present {\it preliminary} results for the decay constants of heavy-light mesons using NRQCD heavy and tadpole improved Clover light quarks. A comparison is made with data obtained using Wilson light quarks. We present an analysis of the 1/M corrections to the decay constants in the static limit and compare with the predictions of HQET.Comment: Contribution to Lattice 95, 4 pages uuencoded compressed postscript fil

Coherent States on Hilbert Modules

We generalize the concept of coherent states, traditionally defined as special families of vectors on Hilbert spaces, to Hilbert modules. We show that Hilbert modules over $C^*$-algebras are the natural settings for a generalization of coherent states defined on Hilbert spaces. We consider those Hilbert $C^*$-modules which have a natural left action from another $C^*$-algebra say, $\mathcal A$. The coherent states are well defined in this case and they behave well with respect to the left action by $\mathcal A$. Certain classical objects like the Cuntz algebra are related to specific examples of coherent states. Finally we show that coherent states on modules give rise to a completely positive kernel between two $C^*$-algebras, in complete analogy to the Hilbert space situation. Related to this there is a dilation result for positive operator valued measures, in the sense of Naimark. A number of examples are worked out to illustrate the theory