Theoretical Physics

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Questions related to Theoretical Physics

Why we don't need to do work, for pushing an excited system to its stable ground state (It comes by own)?

Physicists can answer this question.

02 February 2016 3,103 6 View

Which are the most favorite/reliable hybrid functionals for the accurate prediction of band gap?

References please. Could any one tell me which hybrid functional is the most computational expensive and which one is the least expensive to calculate accurate band gap of solids?

02 February 2016 5,994 3 View

Is it a necessary condition to demand that the derivative makes the degree of the polynomial be decressed by one when we define a deformed derivative?

02 February 2016 1,250 2 View

Minimum mass bound in AdS space suggests that sufficiently small perturbations will NOT lead to black hole formation in AdS space?

http://arxiv.org/abs/1508.03832 and http://arxiv.org/pdf/1104.3702v5.pdf How do we reconcile these two results?

02 February 2016 3,365 1 View

What do we mean by the F2g mode for YSZ/Zirconia in Raman Spectroscopy?

According, cubic Zirconia/YSZ shows a broad Raman peak centered at ~ 605 cm-1 corresponding to the F2g mode. I want to know the physical interpretation of the F2g mode

02 February 2016 8,967 1 View

Is there any analytical expression for wave function in the case of potential well and finite barrier like in alpha decay?

We believe, that alpha particle goes out of nuclei with probability ~exp(-gamma*t), but this is only asymptotic formula. Can we choose some potential, where the formula will be "exact"?

01 February 2016 4,240 6 View

Could someone point me to an attempt to write down the indistinguishability principle in the Lorentz covariant form?

When we transpose particles in the non-relativistic quantum mechanics we write down T \psi(t, x_1, x_2) = a \psi(t, x_2, x_1). Of course, we cannot write this down in another frame, since there...

13 January 2016 1,673 31 View

Is the frame-dragging effect of Kerr metric cumulative?

What would be the frame dragging effect on earth today after 4.5 billion years? Could it be observable?

05 January 2016 4,297 30 View

Is the frame-dragging effect of Kerr metric cumulative?

What would be the frame dragging effect on earth today after 4.5 billion years? Could it be observable?

01 January 2016 7,361 31 View

What are "strings" in string theory made of?

Physics has a lot of abstracts like energy, or momentum that are properties of something. Is there a something equivalent for strings? Something that can be related back to what I can sense...

01 January 2016 8,225 77 View

What are works done on the effects of single impurity in bosonic systems ? Mainly for single impurity effects on lattice of granular superconductors ?

I have been working on lattice of superconducting grains and the corresponding phase oscillations. So, I would like to know about the literature on single impurity effects on this type of materials.

01 January 2016 2,783 1 View

Why in SR light has constant speed?

Constancy of light speed in all inertial systems in SR is somehow hard to understand. Do we have some common explanation ?

01 January 2016 4,782 66 View

What is the occupation number of energy levels in a Bose non-degenerate gas?

A gas consisting in identical bosons, say, atoms with integer spin, obeys at sufficiently low temperatures the Bose-Einstein statistics. Let's assume for simplicity that the only relevant quantum...

01 January 2016 9,829 4 View

Which is the best way to integrate the Duffing equation in the particular case of capsize equation?

The Duffing equation, d2x/dt2+beta*dx/dt+x-x3=F cos(omega*t), is called the capsize equation (it describes the rolling motion of a ship in waves). For fixed beta and omega, the numerical...

01 January 2016 9,205 6 View

Does anybody know Hook equation in relativistic case?

It's well known, that in Special Relativity (SR) there can't be rigid bodies, so sorta Hook equation must account any body deformation. Consider two cubes, moving to each other with v~c. How they...

12 December 2015 1,147 28 View

Is there some contradiction between Feynman's path integral and the relativity?

A well known formula in Feynman's path integral formalism is (1) K(rA, rB) = ∫ K(rA, rC) K(rC, rB) drC, where K(rA, rB) is the amplitude of probability to reach the position rB at the time tB,...

12 December 2015 5,184 62 View

Nature's fundamental (eg, fine-structure and cosmological) constants have values in the small, highly improbable range that allows life to exist. Why?

This is highly improbable according to current physics theories, the probability being the product of already low probabilities.

12 December 2015 5,490 27 View

How can we apply Lorentz transformation in this particular senario?

Suppose a spaceship is moving in positive x-direction with a velocity v There are two laser guns at both ends along x-axis. Next we fire both guns simultaneously. For an observer inside the...

12 December 2015 2,494 21 View

Why is the powerful reverse bra-ket method not used more intensively?

Dirac introduced the bra-ket notation that strongly popularized the usage of Hilbert spaces. The bra’s and ket’s ease the handling of Hilbert vectors and the usage of the inner products of these...

16 November 2015 4,536 10 View

Which one of two definitions of vector equality are valid?

Two vectors AB and CD are equivalent, (1) if components of vectors are equal ABk=CDk, k=0,1,2,3. (2) if (AB.CD)=|AB||CD| and |AB|=|CD|, where (AB.CD) ls the scalar product of two vectors. In the...

11 November 2015 3,065 24 View

Can anyone see a flaw in my thought experiment that concludes that interferometers are not capable of detecting gravitational waves?

In my thought experiment, I visualize a photon traveling through space. The photon first travels through point A, which is far away from the sun. It then travels through point B, which is very...

11 November 2015 7,582 7 View

Does the uncertainty principle violate the conservation of energy law?

Aephraim Steinberg of the University of Toronto in Canada and his team of researchers have performed measurements of photons and showed that the act of measuring can introduce less uncertainty...

11 November 2015 6,874 82 View

Why is the powerful reverse bra-ket method not used more intensively?

11 November 2015 8,909 11 View

Why planet Earth rotates about its own axis?

Theoretical physics, Fundamental physics, Astronomy, Astrophysics

11 November 2015 4,096 3 View

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