Collection Number C10053
Collection Date -
Collection Type Conference/School
PIAF Workshop Brisbane
Tamara Davis The last decade of astrophysics has shown more than ever before that cosmology can teach us about the nuts-and-bolts of basic physics. This has been driven by the discovery of the accelerating universe (dark energy) --- the theories being proposed to explain dark energy often invoke new physics such as brane-worlds arising from fledgling models of quantum-gravity.
Basic epistemological considerations suggest that the laws of nature should be scale invariant and no fundamental length scale should exist in nature. Indeed, the standard model action contains only two terms that break scale invariance: the Einstein-Hilbert term and the Higgs mass term.
I will present a recent result showing that general relativity admits a dual description in terms of a 3D scale invariant theory. The dual theory was discovered by starting with the basic observation that, fundamentally, all observations can be broken down into local comparisons of spatial configurations. Thus, absolute local spatial size is unobservable. Inspired by this principle of "relativity of size", I will motivate a procedure that allows the refoliation invariance of general relativity to be traded for 3D local scale invariance.
Tony Downes The geometry of space-time can only be determined by making measurements on physical systems. The ultimate accuracy achievable is then determined by quantum mechanics which fundamentally governs these systems. In this talk I will describe uncertainty principles constraining how well we can estimate the components of a metric tensor describing a gravitational field. I shall outline a number of examples which can be easily constructed with a minimum of mathematical complexity.
Maki Takahashi We present a formalism describing the transport of the quantum spin state of massive fermions in curved space-time for the purpose of studying relativistic quantum information phenomena such as entanglement and teleportation. We are concerned with answering the elementary question of how the state of a qubit transforms as it moves through a curved space-time manifold. This transport equation takes the form of the Fermi-Walker transport of a two component spinor, which will be shown to be unitary in the spinor's rest frame.
Shan Gao We investigate the validity of the field explanation of the wave function by analyzing the mass and charge density distributions of a quantum system. According to protective measurement, a charged quantum system has effective mass and charge density distributed in space, proportional to the square of the absolute value of its wave function.
Karim Thebault Canonical quantization techniques are generally considered to provide one of the most rigorous methodologies for passing from a classical to a quantum description of reality. For classical Hamiltonian systems with constraints a number of such techniques are available (i.e. gauge fixing, Dirac constraint quantization, BRST quantization and geometric quantization) but all are arguably equivalent to the quantization of an underlying reduced phase space that parameterizes the "true degrees of freedom" and displays a symplectic geometric structure.
The complementary contributions of free will, indeterminism and signalling to models of quantum correlations
To model statistical correlations that violate Bell inequalities (such as singlet state correlations), one must relax at least one of three physically plausible postulates: measurement independence (experimenters can freely choose measurement settings independently of any underlying variables describing the system); no-signalling (underlying marginal distributions for one observer cannot depend on the measurement setting of a distant observer), and determinism (all outcomes can be fully determined by the values of underlying variables). It will be shown that, for any given model, one may quant
Quantum correlations cannot be given any classical explanation that would satisfy Bell's local causality assumption. This quite intriguing feature of quantum theory, known as quantum non-locality, has fascinated physicists for years, and has more recently been proven to have interesting applications in quantum information processing. To properly understand the power of quantum non-locality, it is important to be able to quantify it.