117773621
Quantum Stress Tensor Fluctuations and their Physical Effects
We summarize several aspects of recent work on quantum stress tensor fluctuations and their role in driving fluctuations of the gravitational field. The role of correlations and anticorrelations is emphasized. We begin with a review of the properties of the stress tensor correlation function. We next consider some illuminating examples of non‐gravitational effects of stress tensors fluctuations, specifically fluctuations of the Casimir force and radiation pressure fluctuations. We next discuss passive fluctuations of spacetime geometry and some of their operational signatures. These include luminosity fluctuations, line broadening, and angular blurring of a source viewed through a fluctuating gravitational field. Finally, we discuss the possible role of quantum stress tensor fluctuations in the early universe, especially in inflation. The fluctuations of the expansion of a congruence of comoving geodesics grows during the inflationary era, due to non‐cancellation of anticorrelations that would have occurr...
119279483
Gravity Waves from Quantum Stress Tensor Fluctuations in Inflation
We consider the effects of the quantum stress tensor fluctuations of a conformal field in generating gravity waves in inflationary models. We find a non-scale invariant, non-Gaussian contribution which depends upon the total expansion factor between an initial time and the end of inflation. This spectrum of gravity wave perturbations is an illustration of a negative power spectrum, which is possible in quantum field theory. We discuss possible choices for the initial conditions. If the initial time is taken to be sufficiently early, the fluctuating gravity waves are potentially observable both in the CMB radiation and in gravity wave detectors, and could offer a probe of transplanckian physics. The fact that they have not yet been observed might be used to constrain the duration and energy scale of inflation.
119118161
Quantum noise in the mirror-field system: A field theoretic approach
Abstract We revisit the quantum noise problem in the mirror–field system by a field-theoretic approach. Here a perfectly reflecting mirror is illuminated by a single-mode coherent state of the massless scalar field. The associated radiation pressure is described by a surface integral of the stress-tensor of the field. The read-out field is measured by a monopole detector, from which the effective distance between the detector and mirror can be obtained. In the slow-motion limit of the mirror, this field-theoretic approach allows to identify various sources of quantum noise that all in all leads to uncertainty of the read-out measurement. In addition to well-known sources from shot noise and radiation pressure fluctuations, a new source of noise is found from field fluctuations modified by the mirror’s displacement. Correlation between different sources of noise can be established in the read-out measurement as the consequence of interference between the incident field and the field reflected off the mirror. In the case of negative correlation, we found that the uncertainty can be lowered than the value predicted by the standard quantum limit. Since the particle-number approach is often used in quantum optics, we compared results obtained by both approaches and examine its validity. We also derive a Langevin equation that describes the stochastic dynamics of the mirror. The underlying fluctuation–dissipation relation is briefly mentioned. Finally we discuss the backreaction induced by the radiation pressure. It will alter the mean displacement of the mirror, but we argue this backreaction can be ignored for a slowly moving mirror.
117599682
Quantum fluctuations of the stress tensor
15106810
Stress Tensor Fluctuations and Passive Quantum Gravity
The quantum fluctuations of the stress tensor of a quantum field are discussed, as are the resulting space-time metric fluctuations. Passive quantum gravity is an approximation in which gravity is not directly quantized, but fluctuations of the space-time geometry are driven by stress tensor fluctuations. We discuss a decomposition of the stress tensor correlation function into three parts, and consider the physical implications of each part. The operational significance of metric fluctuations and the possible limits of validity of semiclassical gravity are discussed.
119211117
Trapping effects on inflation
We develop a Lagrangian approach based on the influence functional method so as to derive self-consistently the Langevin equation for the inflaton field in the presence of trapping points along the inflaton trajectory. The Langevin equation exhibits the backreaction and the fluctuation-dissipation relation of the trapping. The fluctuation is induced by a multiplicative colored noise that can be identified as the the particle number density fluctuations and the dissipation is a new effect that may play a role in the trapping with a strong coupling. In the weak coupling regime, we calculate the power spectrum of the noise-driven inflaton fluctuations for a single trapping point and studied its variation with the trapping location. We also consider a case with closely spaced trapping points and find that the resulting power spectrum is blue.
93987437
Parameters of the Charge Distribution of Deformed Nuclei
Precise measurements, using a stable high resolution Ge(Li) spectrometer have been made of the K (2P-1S) and L (3d-2P) muonic X-ray spectra of eight even-even rare-earth nuclei: 150Nd, 152Sm, 162Dv, 164Dy, 168Er, 170Er, 182W, 184W, and 186W (1). From these measurements values of the parameters of the nuclear charge density 
 
$$\text{ }\!\!\rho\!\!\text{ }\left( \text{r} \right)\,\text{=}\,\mathop{\text{ }\!\!\rho\!\!\text{ }}_{\text{o}}\,{{\left[ \text{1}\,\text{+}\,\text{exp}\,\frac{\text{r-c}\left[ \text{1+ }\!\!\beta\!\!\text{ }\mathop{\text{Y}}_{\text{20}}\left( \text{ }\!\!\theta\!\!\text{ } \right) \right]}{\text{a}} \right]}^{\text{-1}}}$$ 
 
have been determined.
43335620
The Universal Fermi Interaction and the Conserved Vector Current in Beta Decay
The theoretical formulation of the (V-- A) fermi interac tion is shown. The requirements of the continuity equatio of the electromagnetic current are discussed in order to lead to the formulation of the conserved vector current theory and the unique properties arising from it. The present status of the question of equality between the vector coupling constant g/sub v/ of beta decay and the Fermi constant g/sub u/ of mu decay is examined. Four types of experiments to test the CVC hypothesis are discussed. (auth) O H21308 A procedure was developed for measuring photoneutron yields from targets of grent thickness by the method of induced activity. The dependence of the photoneutron yields on the electron energy, on /sup 16/O nuclei over an energy range of 19 to 66 Mev, and on /sup 63/Cu nuclei over an energy range of 13 to 50 Mev was investigated. The electron beam from a linear accelerator was monitored by means of a secondary emission monitor. The measured values of the photoneutron yields agree with the data of others; they proved to be haif the calculated values obtained by means of the Belenky-Tamm equilibrium spectrum. (auth)
120491282
Accessibility of the stochastic gravitational wave background from magnetars to the interferometric gravitational wave detectors
121147087
The Angular Correlation of Scattered Annihilation Radiation
122705362
The Resonance Process and the Intensity Anomaly in Muonic 127I
It has been known for some time that the intensity ratio between the (2p3/2-Is1/2) and (2p1/2-Is1/2) muonic X-rays for 127I is anomalously smaller than the theoretical value 1.95. Several theorists(1),(2),(3) have suggested that this may be explained by nuclear resonance excitation. We have observed the muonic N, M, L and K X-rays from 127I, and have calculated a theoretical spectrum within the framework of a resonance process. The resonance is between the 2p fine structure splitting and the nuclear ground and the first excited states. A satisfactory fit to the experimental data has been obtained. From this fit we have determined the M1 and E2 hfs constants for the is and 2p states, and have obtained a quantitative interpretation of the observed intensity ratios.