50(1) | JAN–FEB 2013 In a recent paper [1], originally written to explain the origin of experimental configurations to determine the quantum entanglement of photons traveling in opposite directions, the issue of the corresponding probability amplitude surfaced. As it turns out, Australian physicists J C Ward and R H Dalitz played key roles in this field, roles that are largely unrecognised, or ...

The Photon Collider option of a Linear Collider (LC) is based on laser photon back-scattering on high energy electrons. The maximum photon energy is 205 GeV for a laser with λ = 1.06μm and an electron beam energy of 250 GeV. A high degree of polarisation with opposite helicities of the electron and the laser photon is crucial for obtaining a peaked spectrum of high energy polarised photons clos...

The dark photon is a massive hypothetical particle that interacts with the Standard Model by kinetically mixing visible photon. For small values of parameter, photons can evade cosmological bounds to be viable matter candidate. Due similarities electromagnetic signals generated axions, several on are simply reinterpretations historical set axion haloscopes. However, has property does not: an in...

In a series of paper, it has been shown that the distribution of polarisation position angles for visible light from quasars is not random in extremely large regions of the sky. As explained in a recent article, the measurement of vanishing circular polarisation for such quasars is an important problem for a mechanism involving the mixing with axionlike particles in external magnetic fields. In...

CP property of the Higgs at the γγ colliders using t ¯ t production. ABSTRACT We present results of an investigation to study CP violation in the Higgs sector in t ¯ t production at a γγ-collider, via the process γγ → φ → t ¯ t where the φ is a scalar with indeterminate CP parity. The study is performed in a model independent way parametrising the CP violating couplings in terms of six form fac...

Axion-photon mixing has been proposed as an alternative to acceleration as the explanation for supernovae dimming. We point out that the loss of photons due to this mixing will induce a strong asymmetry between the luminosity, dL(z), and angular-diameter distance, dA(z), since the latter is unaffected by mixing. In a first search for such asymmetry we introduce an amplitude A, such that A = 1 i...

Abstract The generation of entanglement between distant atoms via single photons is the basis for networked quantum computing, a promising route to large-scale trapped-ion and trapped-atom processors. Locating emitter within an optical cavity provides efficient matter-light interface, but mirror-induced birefringence introduces time-dependence polarisation produced. We show that such ‘polarisat...

Photon entanglement is an essential ingredient for linear optics quantum computing schemes, quantum cryptographic protocols and fundamental tests of quantum mechanics. Here we describe a setup that allows for the generation of polarisation-entangled N -photon states on demand. The photons are obtained by mapping the entangled state of N atoms, each of them trapped inside an optical cavity, onto...

Quantum phenomena such as vacuum polarisation in curved spacetime induce interactions between photons and gravity with quite striking consequences, including the violation of the strong equivalence principle and the apparent prediction of ‘superluminal’ photon propagation. These quantum interactions can be encoded in an effective action. In this paper, we extend previous results on the effectiv...

Results on elastic electroproduction of ρ mesons are presented for a photon virtuality in the range 1 < Q < 60 GeV and for a hadronic centre of mass energy in the range 30 < W < 140 GeV. The shape of the (ππ) mass distribution is discussed and measurements of the cross section dependences on Q, W and t (the four-momentum transfer squared to the proton) are presented. The full set of ̺ spin densi...