Abstract

Abstract

Abstract

This talk is a limited overview of the principles and techniques ofinterferometry with ‘matter waves’ – quantum interferometry to be moreprecise. I will focus on interferometers employing laser-cooled neutralatoms. The variety of ways in which atoms with internal states can respond tofields of external perturbations and ‘interfere’ is reflected in the richvariety of atom interferometers that can explore avenues not accessible tooptical interferometers. In particular, I will discuss the operation ofquantum interferometers in a gravitational field, stressing its ability tomeasure gravitational and inertial fields with unprecedented sensitivity. Thisalso leads to some fundamental issues of interpretation in the context ofgravitational redshift and time dilation. I will end with discussion whethergravimetry with quantum interferometers is equivalent to a measurement of thegravitational time dilation.

Abstract

I will discuss a new paradigm for physics of dynamics and relativity that is necessary to be consistent with modern cosmology. The fact that the fundamental theories of physics were completed well before any significant knowledge about the real universe and its enormous gravity was available necessitates a re-examination of these theories, especially that of dynamics and relativity. The results of this analysis, along with several experimental facts, reveal that the gravity of the cosmos determines the laws of motion and the propagation of light. In a grand generalization of Machian thought, Newton’s law of motion and the equivalence principle are natural consequences of the gravitational effect in the massive universe. All effects of relativity of motion, like length contraction and time dilation are in fact cosmic gravitational effects. Electrodynamics has physical effects that go beyond special relativity, requiring new experiments and analysis. Indeed, new experiments in our laboratory indicate clearly that the one-way speed of light is not a universal constant relative to moving observers, shattering the most cherished of our beliefs in physics and necessitating replacement of the special theory of relativity with a new ‘Cosmic Relativity’.

Abstract

X-ray multilayers (MLs) – layered synthetic one-dimensional periodic microstructures – are playing an important role in the exploitation of x-rays, particularly soft x-ray/extreme ultra violet (XUV) region of the electromagnetic spectrum. However, understanding basic physics of x-ray MLs and controlling atomic distribution (hence surface/interface) over atomic depth scales in these nano-structured ML systems are crucial for optimum performance of optical elements. In this talk I will present the current state-of-the art research directions in the area of physics (basic and applied) of x-ray ML optics. I will discuss surface/interface studies through representative results of different material combinations. The talk will also cover correlation of structural parameters with tunable properties of x-ray MLs suitable for a variety of applications using synchrotron radiation.The second part of the talk will focus to uncover the underlying mechanism of resonance principle in x-ray scattering technique for basic surface/interface science with high sensitivity and unique additional feature compared to conventional x-ray scattering. Conventional x-ray reflectivity (XRR) probes spatial electron density distribution (within sensitive limit) but not directly atomic composition of the layer. A novel approach will be addressed not only the possible solution to low contrast physics issue of XRR but also an innovative approach to combine structural with chemical analysis using a single resonant scattering technique known for depth resolving sensitivity. We predicted resonant x-ray scattering combines layer sensitivity of reflectivity technique with short-range structural sensitivity such as chemical composition surrounding the resonating atom of spectroscopic technique due to element specificity and contrast variation mechanism of resonance effect. The sensitivity of resonant scattering to the presence of different chemical species around the resonating atoms is analogous to using deuteration as marker in neutron reflectivity. Novel idea will be demonstrated through representative results of different types of basic surface/interface studies near Si L-edge and boron K edge using synchrotron radiation..