scholarly journals Gauge-invariant tensor perturbations induced from baryon-CDM relative velocity and the B -mode polarization of the CMB

2021 ◽  
Vol 104 (8) ◽  
Author(s):  
James Gurian ◽  
Donghui Jeong ◽  
Jai-chan Hwang ◽  
Hyerim Noh
Keyword(s):  
Relative Velocity ◽  
Gauge Invariant ◽  
Invariant Tensor ◽  
Tensor Perturbations

scholarly journals Scale-invariant tensor spectrum from conformal gravity

2015 ◽  
Vol 30 (32) ◽  
pp. 1550172 ◽  
Author(s):  
Yun Soo Myung ◽  
Taeyoon Moon
Keyword(s):  
Power Spectrum ◽  
Mass Parameter ◽  
Conformal Gravity ◽  
De Sitter ◽  
Scale Invariant ◽  
Tensor Power ◽  
Invariant Tensor ◽  
Tensor Perturbations

We study cosmological tensor perturbations generated during de Sitter inflation in the conformal gravity with mass parameter [Formula: see text]. It turns out that tensor power spectrum is scale-invariant.

Helicity decomposition of metric perturbations

2018 ◽  
Author(s):  
Michele Maggiore
Keyword(s):  
Degrees Of Freedom ◽  
Energy Momentum Tensor ◽  
Momentum Tensor ◽  
Invariant Metric ◽  
Gauge Invariant ◽  
Tensor Perturbations

Decomposition of the perturbations over FRW into scalar, vector and tensor perturbations. Physical and unphysical degrees of freedom. Gauge-invariant metric perturbations, Bardeen variables. Gauge-invariant perturbations of the energy-momentum tensor

scholarly journals A gauge-invariant tensor calculus

1927 ◽  
Vol 116 (775) ◽  
pp. 603-623 ◽  
Keyword(s):  
Differential Equations ◽  
Affine Structure ◽  
Tensor Calculus ◽  
Gauge Invariant ◽  
Invariant Tensor ◽  
General Affine

It has been pointed out by Weyl, Eisenhart, Veblen and others, that the differential equations of geodesics in a manifold with a general affine structure do not remain unchanged in form when a new parameter is adopted. If in the equation d 2 x i / d ז 2 + ┌ i rs dx r / dז dx 8 / dז = 0 ז is replaced by (ז), the resulting equation is d 2 x i / d ז̄ 2 + ┌ i rs dx r / dז̄ dx 8 / dז̄ – dז̄ / dז d 2 ז / dז 2 dx i / dז̄ = 0.

scholarly journals The impulse-energy tensor of material particles

1944 ◽  
Vol 182 (990) ◽  
pp. 302-318
Keyword(s):  
Electromagnetic Field ◽  
Momentum Density ◽  
Momentum Operator ◽  
General Construction ◽  
Energy Tensor ◽  
Gauge Invariant ◽  
Invariant Tensor ◽  
Derivatives Of

The following is a direct and general construction, from the field quantities of the electrons and mesons and their derivatives, of a real, symmetrical and gauge-invariant tensor T kl whose divergence to l is — 1 times the four-force f k experienced by the matter. Interpreting T kl as the impulse-energy tensor of the material particles, for the case of no electromagnetic field the energy-momentum density obtained from T k4 is compared with that obtained from treating (ℏ/ i ) (∂/∂x k ) as the energy-momentum operator. Further, in the general case the Hamiltonian of the matter is compared with ∫ T 44 dxdydz . Both times, the two quantities compared agree apart from small modifications.

Rapid Freezing of Freeze-Etch Specimens

1980 ◽  
Vol 38 ◽  
pp. 752-755
Author(s):  
A. Elgsaeter ◽  
T. Espevik ◽  
G. Kopstad
Keyword(s):  
Low Temperature ◽  
Metal Surface ◽  
Relative Velocity ◽  
Thermal Contact ◽  
High Rate ◽  
Rapid Freezing ◽  
Temperature Decrease ◽  
Freeze Etching

The importance of a high rate of temperature decrease (“rapid freezing”) when freezing specimens for freeze-etching has long been recognized1. The two basic methods for achieving rapid freezing are: 1) dropping the specimen onto a metal surface at low temperature, 2) bringing the specimen instantaneously into thermal contact with a liquid at low temperature and subsequently maintaining a high relative velocity between the liquid and the specimen. Over the last couple of years the first method has received strong renewed interest, particularily as the result of a series of important studies by Heuser and coworkers 2,3. In this paper we will compare these two freezing methods theoretically and experimentally.

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