Testing extra dimensions with boundaries using Newton's law modifications

Extra dimensions with boundaries are often used in the literature, to provide phenomenological models that mimic the standard model. In this context, we explore possible modifications to Newton's law due to the existence of an extra-dimensional space, at the boundary of which the gravitational field obeys Dirichlet, Neumann or mixed boundary conditions. We focus on two types of extra space, namely, the disk and the interval. As we prove, in order to have a consistent Newton's law modification (i.e., of the Yukawa-type), some of the extra-dimensional spaces that have been used in the literature, must be ruled out.Comment: Published version, title changed, 6 figure

Wrongful convictions of refugees and asylum seekers: responses by the Criminal Cases Review Commission

The Criminal Cases Review Commission (CCRC) reviews possible miscarriages of justice in England, Wales and Northern Ireland when applicants have exhausted other avenues of appeal, with a view to referring unsafe convictions back to the appeal court. This article considers the CCRC’s handling of applications from refugees and asylum seekers who claim to have been wrongly convicted of entering the UK illegally. These cases commonly relate to people who could not obtain travel documents lawfully and were erroneously advised by defence lawyers that they should plead guilty. The article first examines the sources of these wrongful convictions by reviewing CCRC referrals to the appeal court. It then reviews the CCRC’s wider engagement with other criminal justice agencies in an effort to prevent further wrongful convictions of refugees and asylum seekers. The failing of the criminal justice agencies to properly protect refugees and asylum seekers reflects a wider anxiety about the negative effects of immigration, and the societal appetite to use punitive measures to control immigration. The article concludes by arguing that the CCRC’s campaign was effective, and demonstrates the importance of inter-agency communication in preventing miscarriages of justice

Beyond the ‘wow factor’? Climate resilient green infrastructure for people and wildlife

Covid-19 and COP26 both amplified calls from the environment sector for greater support for greenspace management globally. As the future of our planet and population is threatened by a global pandemic, escalating mental health challenges and the interrelated climate and biodiversity crises, there is a growing awareness of the potential for the intersecting roles of greenspace (GS), green infrastructure (GI) and nature-based solutions (NBS) to meet the myriad socio-economic and ecological of modern society (Frantzeskaki, 2019; Venkataramanan et al., 2020). Unfortunately, their potential to address these challenges remains undervalued by many, and thus underfunded, (Mell, 2021). Presenting examples of ‘research into action’, we advocate greenspace management to maximise benefits for people and wildlife. We draw on research from UK to consider how and why different people react to landscapes of varying aesthetic and biodiversity quality (Hoyle et al. 2017a), proposing an alternative approach to biodiversity-friendly greenspace management under austerity. Next, we emphasise the urgency of ‘futureproofing’ places to adapt to changing climate, demonstrating the public acceptability of climate-ready urban GI (Hoyle, 2021). Finally, we discuss how socio-cultural variables and values impact on preferences. We illustrate the benefits of co-creating local NBS with reference to ‘Futureproofing Luton’, a live project engaging diverse partners in the co-production of an educational arboretum-meadow. We propose alternative options open to all natural and built environment and public health professionals to support knowledge exchange promoting more sustainable forms of urban development. Although framed within a UK context, the processes of engagement, best practice exchange, and more effective dialogue, are meaningful across Europe and beyond

Astrophysical implications of hypothetical stable TeV-scale black holes

We analyze macroscopic effects of TeV-scale black holes, such as could possibly be produced at the LHC, in what is regarded as an extremely hypothetical scenario in which they are stable and, if trapped inside Earth, begin to accrete matter. We examine a wide variety of TeV-scale gravity scenarios, basing the resulting accretion models on first-principles, basic, and well-tested physical laws. These scenarios fall into two classes, depending on whether accretion could have any macroscopic effect on the Earth at times shorter than the Sun's natural lifetime. We argue that cases with such effect at shorter times than the solar lifetime are ruled out, since in these scenarios black holes produced by cosmic rays impinging on much denser white dwarfs and neutron stars would then catalyze their decay on timescales incompatible with their known lifetimes. We also comment on relevant lifetimes for astronomical objects that capture primordial black holes. In short, this study finds no basis for concerns that TeV-scale black holes from the LHC could pose a risk to Earth on time scales shorter than the Earth's natural lifetime. Indeed, conservative arguments based on detailed calculations and the best-available scientific knowledge, including solid astronomical data, conclude, from multiple perspectives, that there is no risk of any significance whatsoever from such black holes.Comment: Version2: Minor corrections/fixed typos; updated reference

Tests of the Gravitational Inverse-Square Law below the Dark-Energy Length Scale

We conducted three torsion-balance experiments to test the gravitational inverse-square law at separations between 9.53 mm and 55 micrometers, probing distances less than the dark-energy length scale $\lambda_{\rm d}=\sqrt[4]{\hbar c/\rho_{\rm d}}\approx 85 \mu$m. We find with 95% confidence that the inverse-square law holds ($|\alpha| \leq 1$) down to a length scale $\lambda = 56 \mu$m and that an extra dimension must have a size $R \leq 44 \mu$m.Comment: 4 pages, 6 figure

A Century of Cosmology

In the century since Einstein's anno mirabilis of 1905, our concept of the Universe has expanded from Kapteyn's flattened disk of stars only 10 kpc across to an observed horizon about 30 Gpc across that is only a tiny fraction of an immensely large inflated bubble. The expansion of our knowledge about the Universe, both in the types of data and the sheer quantity of data, has been just as dramatic. This talk will summarize this century of progress and our current understanding of the cosmos.Comment: Talk presented at the "Relativistic Astrophysics and Cosmology - Einstein's Legacy" meeting in Munich, Nov 2005. Proceedings will be published in the Springer-Verlag "ESO Astrophysics Symposia" series. 10 pages Latex with 2 figure

APOLLO: the Apache Point Observatory Lunar Laser-ranging Operation: Instrument Description and First Detections

A next-generation lunar laser ranging apparatus using the 3.5 m telescope at the Apache Point Observatory in southern New Mexico has begun science operation. APOLLO (the Apache Point Observatory Lunar Laser-ranging Operation) has achieved one-millimeter range precision to the moon which should lead to approximately one-order-of-magnitude improvements in the precision of several tests of fundamental properties of gravity. We briefly motivate the scientific goals, and then give a detailed discussion of the APOLLO instrumentation.Comment: 37 pages; 10 figures; 1 table: accepted for publication in PAS

Modeling Repulsive Gravity with Creation

There is a growing interest in the cosmologists for theories with negative energy scalar fields and creation, in order to model a repulsive gravity. The classical steady state cosmology proposed by Bondi, Gold and Hoyle in 1948, was the first such theory which used a negative kinetic energy creation field to invoke creation of matter. We emphasize that creation plays very crucial role in cosmology and provides a natural explanation to the various explosive phenomena occurring in local (z<0.1) and extra galactic universe. We exemplify this point of view by considering the resurrected version of this theory - the quasi-steady state theory, which tries to relate creation events directly to the large scale dynamics of the universe and supplies more natural explanations of the observed phenomena. Although the theory predicts a decelerating universe at the present era, it explains successfully the recent SNe Ia observations (which require an accelerating universe in the standard cosmology), as we show in this paper by performing a Bayesian analysis of the data.Comment: The paper uses an old SNeIa dataset. With the new improved data, for example the updated gold sample (Riess et al, astro-ph/0611572), the fit improves considerably (\chi^2/DoF=197/180 and a probability of goodness-of-fit=18%