Neutron Interferometry 2nd Edn

Abstract

In this new edition we have retained the overall structure of the original book. It now consists of 12 chapters. We have shifted some material from later chapters to the first chapter. In particular, we have described gravitationally induced quantum interference (COW experiment) and early experiments on spin rotation, spinors, and spin-related phases in Chapter 1. These results have gotten broad attention in recent years and are now described in various standard physics textbooks. This change in format was done with a view of the close connection of these experiments with the atom interferometry field and with the modern ideas on entanglement now permeating all of the modern quantum mechanical literature.Neutron interferometry is a mature technique in experimental physics. The use of the perfect silicon crystal interferometer to accurately measure scattering lengths of many isotopes is given in Chapter 3. Very accurate measurements of the neutron scattering lengths of the proton, deuteron, and He-3 have been carried out in recent years. These results confine the parameters in various theoretical models of few-body nuclear physics.Chapter 4 is retitled "Coherence and Decoherence," so as to include many new topics connected to the current emphasis in certain areas of physics related to how coherent quantum systems decohere and evolve into systems described by classical Lagrangian and Hamiltonian mechanics. The quantum concepts of entanglement, contexuality, squeezing, Wigner functions, interactions of quantum systems with the environment, post selection experiments, measures of distinguishability, intensity-intensity correlations, and Bell's inequalities are the general topics of this expanded chapter. "Contexuality and Kochen-Specker Phenomena" are discussed in a new Chapter 7.Our original Chapter 8 dealing with forthcoming and more speculative experiments is now Chapter 10. Some of those experiments have advanced considerably over the intervening 12 years since the publication of the 1st edition. Experiments related to searches for non-Newtonian gravity at short distances have been pursued in various confined geometries, such as transmission through narrow slits. Related ideas, called "bouncing ball" experiments, have successfully observed quantized states of ultra-cold neutrons in the Earth's gravity. An experiment designed to observe the Anandan acceleration has not yet been attempted. The observation of relativistic proper time effects, as suggested in Chapter 8, occurs at the level of 10 -9 . Suggested observation of such effects in atom beam interferometry, related to a gravitational redshift, has generated interesting, but controversial papers. Perhaps there is a way to pursue such effects with neutron interferometry utilizing the Pendellösung interference fringes, as discussed in this chapter on "Gravitational, Inertial, and Motional Effects." A feasible time-dependent Fizeau experiment is described to study new motional effects and for the cooling of neutron beams.Various new techniques and experiments of...

Observation of a quantum Cheshire Cat in a matter-wave interferometer experiment

“…The neutron’s spin wavefunction is then given by | S x ;+›. Subsequently, the neutrons enter a triple-Laue interferometer 28 31 . Inside the interferometer, a spin rotator in each beam path allows the generation of the preselected state .…”

“…In this work, we prepare and measure the Cheshire Cat states by means of neutron interferometry 28 , which has already been successfully used to study many other purely quantum mechanical effects 29 30 31 . The experimental results suggest that the system behaves as if the neutrons go through one beam path, while their magnetic moment travels along the other.…”

Visibility simulation of realistic grating interferometers including grating geometries and energy spectra

“…The particle wave duality has been proposed a long time ago [10] and manifests itself in the deBroglie equation that assigns a wavelength to massive particles. Thus neutrons can be considered a wave and wave optical descriptions of interference effects can be used to understand the nGI [11] as well as the xGI.…”

Precision Measurement of the Neutron Scattering Length of He4 Using Neutron Interferometry

“…A neutron interferometer [14][15][16] splits the matter wave of a neutron into two coherent paths using Bragg diffraction in single crystal silicon and then reflects and recombines them, producing interference that is observable by neutron counters located behind the crystal. A target placed in one beam path of the neutron interferometer produces a relative phase shift φ = −N λbl where N is the atomic number density, l is the target path length, λ is the neutron wavelength, and b is the real part of the average bound neutron scattering length in the target.…”