Device-Independent Relativistic Quantum Bit Commitment

We examine the possibility of device-independent relativistic quantum bit commitment. We note the potential threat of {\it location attacks}, in which the behaviour of untrusted devices used in relativistic quantum cryptography depends on their space-time location. We describe relativistic quantum bit commitment schemes that are immune to these attacks, and show that these schemes offer device-independent security against hypothetical post-quantum adversaries subject only to the no-signalling principle. We compare a relativistic classical bit commitment scheme with similar features, and note some possible advantages of the quantum schemes

BGS Sigma 2012 open source user guide

The British Geological Survey began developing digital field mapping systems in 1989. However, it was apparent that the commercially available hardware was not suitable at that time. In 2001, we revisited the topic under the System for Integrated Geoscience Mapping (SIGMA) programme. By 2003, BGS had developed a PDA (personal digital assistant) field system, which was superseded in 2005, when we began deploying a beta system on rugged Tablet PCs. The Tablet PC system, which we called BGS•SIGMAmobile was used by BGS in mapping projects across the UK as well as overseas. It first became available in Open Source form, in June 2009 via the BGS website, www.bgs.ac.uk, under an agreement which stipulates that updates and modifications must be supplied to BGS in order to stimulate further developments. In 2011/2012, BGS•SIGMAmobile was rewritten in .NET and combined with our office based mapping software BGS•SIGMAdesktop within ArcGIS 10.x to create BGS•SIGMA 2012. It is envisaged that future releases will be made available from the BGS website incorporating new modules, modifications and upgrades supplied by BGS and external users of the system. This document has been written to guide users through the installation and use of BGS•SIGMA 2012 (mobile and desktop), which is the third free release. We are happy to receive feedback and modifications emailed to [email protected]

Laws of Nature as Constraints

The laws of nature have come a long way since the time of Newton: quantum mechanics and relativity have given us good reasons to take seriously the possibility of laws which may be non-local, atemporal, ‘all-at-once,’ retrocausal, or in some other way not well-suited to the standard dynamical time evolution paradigm. Laws of this kind can be accommodated within a Humean approach to lawhood, but many extant non-Humean approaches face significant challenges when we try to apply them to laws outside the time evolution picture. Thus for proponents of non-Humean approaches to lawhood there is a clear need for a novel non-Humean account which is capable of accommodating these sorts of laws. In this paper we propose such an account, characterizing lawhood in terms of constraints, which are understood as a form of modal structure. We demonstrate that our proposed realist account can indeed accommodate a large variety of laws outside the time evolution paradigm, and describe some possible applications to important philosophical problems

Disappearing Without a Trace: The Arrows of Time in Kent's Solution to the Lorentzian Quantum Reality Problem

Most existing proposals to explain the temporal asymmetries we see around us are sited within an approach to physics based on time evolution, and thus they typically put the asymmetry in at the beginning of time in the form of a special initial state. But there may be other possibilities for explaining temporal asymmetries if we don't presuppose the time evolution paradigm. In this article, we explore one such possibility, based on Kent's `final-measurement' interpretation of quantum mechanics. We argue that this approach potentially has the resources to explain the electromagnetic asymmetry, the thermodynamic asymmetry, the coarse-graining asymmetry, the fork asymmetry, the record asymmetry, and the cosmological asymmetry, and that the explanations it offers may potentially be better than explanations appealing to a special initial state. Our hope is that this example will encourage further exploration of novel approaches to temporal asymmetry outside of the time evolution paradigm.Comment: Forthcoming in BJP