0
votes
0answers
12 views

References on particle cooling

I am looking for references on the topic of particle and mechanical oscillators cooling, in particular: Doppler cooling Resolved sideband cooling and Lamb-Dicke regime Stokes and anti-stokes modes ...
1
vote
1answer
76 views

Is negative energy(work) less than positive energy(work)?

We cannot talk about magnitudes in case of work, but if someone did (-42 J of work) by stopping a moving object. And if someone did 42 J of work, by pushing something, who did more work? Does it ...
0
votes
1answer
44 views

What happens when a contracted object going at speeds comparable to light is fit in a tight space, but has been brought to rest

What happens when a rod of length L moving at a speed comparable to the speed of light, is made to fit in a space of length say 3/4*L and is brought to rest. Does it exert some force on the walls ...
7
votes
1answer
293 views

Does frame dragging apply to linear motion?

Firstly I will admit I do not understand the real cause of rotational frame dragging and some of the math heavy explanations are too complicated for me. To me frame dragging looks like unsubstantiated ...
1
vote
0answers
37 views

Why is the energy lost due to the internal resistance always equal to $(1/2)CV^{2}$ in a simple capacitor battery circuit? [duplicate]

Suppose we have simple circuit in which a battery of EMF $E$ is connected to a capacitor of capacitance $C$. Work done by battery $W_{b}=CV\times V$ and energy stored in capacitor $=\frac{1}{2}CV^{2}$...
1
vote
3answers
103 views

Modern explanation of the Young experiment with Quantum Field Theory?

In the Young double slit experiment it is possible to detect the arrival of individual photons as well as an interference pattern. It doesn't makes much sense to me that something could be either a ...
2
votes
2answers
176 views

Is the reaction force for a stone hitting a wall infinite?

Let us assume a rigid stone which moves in empty space with a constant speed of $v$. (Or in the air with no friction and drag or you can imagine a free fall with friction). This stone hits a rigid ...
3
votes
3answers
239 views

Difference between DMRG (density matrix renomalization group) and MPS (matrix product states)?

I am learning DMRG recently. I noticed there are many papers both in the DMRG approach and MPS (such as variational matrix product state (VMPS) by F.Verstraete and J.I.Cirac) approach. In my eyes, ...
0
votes
1answer
27 views

How to calculate turning acceleration from a compass? [closed]

I have degree and timestamp and want to calculate the turning acceleration. I what to trigger some code when the compass is turning fast. Is there a mathematic way to get an turning acceleration ...
0
votes
1answer
33 views

anatomy of combustion

I don't understand how energy is released in combustion. We have a reaction of a combustible material with oxygen and this releases energy. In what form is this energy released? It should be some ...
1
vote
1answer
71 views

Force on a charged particle due to an uncharged infinite conducting plate

How can I calculate the force on a charged particle due to an uncharged infinite conducting plate? If there is a small object with positive charge placed above a metal plate, the object induces a ...
0
votes
1answer
25 views

Why does emf of a cell equal to $\frac{F_b d}{q}\;?$

In Concepts of Physics by H.C.Verma, it is written: Some internal mechanism exerts forces on the charges of the battery material. ... We show the force on a positive charge $q$ as $\vec F_b\; .$ ...
0
votes
3answers
93 views

If Gravity acts on the particles in the gas, why don't they accumulate on the lower surface and fall down?

A quantity of gas is enclosed in a metal cylinder fitted with a piston. There are very many gas molecules.The cylinder walls are thermally conducting. Now, the question...
0
votes
1answer
82 views

Maxwell equation correct statements [closed]

Do these four statements correctly define the 4 Maxwell's equations or do I need to add or change something in it ? 1)Gauss's law: The net electric flux passing through any closed surface is $\large \...
0
votes
0answers
30 views

Difference Value of the Specific heats at constant Pressure and Temperature of Real Gases

As in ideal gases, we can have the equation of $C_p=C_v+R$, or to be precise, the difference of the Specific heats of ideal gases at constant pressure and volume is the universal gas constant. But, we ...
0
votes
0answers
93 views

why Hall conductance quantized

When I am studying quantum Hall effect, the quantum Hall conductance can be represented by Green function $\left(\text{up to}\ \frac{e^2}{h}\large \right)$: I cannot understand why it is an integer? ...
2
votes
0answers
57 views

What is the relation between dimension and Quantum Field Theory? How does different dimensions change QFT? [closed]

Does the quantisation rules & field operators for scalar or Dirac fields change with dimension? Most books wrote about 3 spatial dimensions, and then upgraded it to 4 spacetime dimensions, keeping ...
1
vote
0answers
48 views

Thermodynamics: Deriving inner energy from ideal gas equation of state [closed]

If we know equation of state for ideal gas $ PV = NkT$ where $P$ stands for pressure, $V$ for volume, $N$ for number of particles, $k$ is Boltzmann constant and $T$ is temperature, how can one ...
0
votes
2answers
52 views

Is Buoyant force a reaction?

When we fall on water. The surface molecules are pushed down and as a consequence molecules below the surface molecules and molecules beneath them and so on are also pushed down. Some of them are ...
0
votes
0answers
36 views

Sinusoidal variation of a generalised coordinate with its conjugate momentum

The hamiltonian of a system with 2 degrees of freedom is given by: H= 0.5(p12q14+p22q12-2aq1) where 'a' is a constant. I am to show that q1 varies sinusoidally with p1. My attempt was to write down ...
1
vote
1answer
29 views

Working of electric-tester [closed]

How does the circuit gets completed when we put an electric-tester glow when we put it in the +ve terminal, when actually the electrons flow from the -ve terminal ?
2
votes
2answers
289 views

On a molecular level, how does heat transfer take place?

When an ice molecule hits a water molecule, the water molecule adds kinetic energy to the ice molecule. Why do the water molecules lose kinetic energy? In other words, why does heat like to go where ...
0
votes
0answers
127 views

Why doesn't saturation photocurrent depend on frequency of incident ray, keeping intensity constant?

We know that intensity I = nhf, where n is no. of photons striking metal surface per second per unit sq unit area, and f is frequency of incident ray. In the book it was said that if we change the ...
1
vote
2answers
61 views

Light and Gravity

The gravitational force does not affect the speed of light rather affects the frequency of light (hence light changes colors, red to blue and vice-versa). I know this has been verified but I have 2 ...
0
votes
0answers
38 views

Bose-Einstein condensate in external field at finite temperature

Suppose at some finite temperature macroscopically large number of interacting bosons condense to form Bose-Einstein condensate (BEC) with some macroscopic wave function. There also exist excitations ...
1
vote
0answers
36 views

Value of $ \langle x | p \rangle$ [duplicate]

In a context of quantum mechanics, why does: $$ \langle x | p \rangle = \left(\frac{1}{2\pi\hbar}\right)^{3/2} e^{ipx/\hbar} $$ Is there any proof for this?
1
vote
0answers
17 views

Motion in Spaces [duplicate]

How does a shuttle move in the space as, the whole mechanism of a rocket is based on 3rd law of newton but, we can not apply 3rd law of newton in space because there is no reactive force in space?
0
votes
1answer
64 views

Can blue light encounter slower clock time over red?

I am aware that matter with mass experiences dilation and photon is massless. there is no inertial frame where photon is at rest. However, wave form of light has momentum and energy. Blue light wave ...
0
votes
1answer
71 views

Head on collision of two black holes

LHC was built to collide two atomic particles to study contents within them. There are millions and billions of black holes present throughout galaxies. As collision between the galaxies is common in ...
2
votes
3answers
113 views

Why can the divergence of vector potential be anything?

Purcell in his book was deriving the vector potential $\bf A$ using $\text{curl}\;(\text{curl}\; \mathbf A)= \mu_0 \mathbf J\; .$ After some algebra, he came to this: $$-\frac{\partial^2 A_x}{\...
1
vote
1answer
92 views

Why phase velocity of light is slower in a dielectric than vacuum?

Why does light speed suffer a reduction when it passes through a homogeneous dielectric medium? I know my math says so, i.e.- a highly polarizable ($\chi$) medium is associated with high $\epsilon$ (=$...
3
votes
0answers
43 views

Sources for black hole geodesic orbits

I am looking for good sources that discuss both Kerr and Schwarzschild particle orbits (geodesics). Most sources write down the geodesic equations, constants of motion and the Hamiltonian, but do not ...
1
vote
1answer
51 views

The point of charge neutrality in the Hydrogen Atom

If we treat the Hydrogen Atom like the Bohr model then we have a proton in the center with an electron orbiting at some radius (the Bohr radius). In this picture you can imagine the electric field ...
1
vote
1answer
204 views

Understanding Noether's theorem rigorously

I've known about Noether's theorem for some time and reading some things about it recently I've realised I haven't completely understood it. In that case I've been trying to understand a more rigorous ...
1
vote
1answer
62 views

Energy paradox in fluid mechanics

In a fluid, the specific mechanical energy $$e_{mech}= \frac{P}{\rho} + \frac{v^2}{2} + gz$$. Where $P$ is the static pressure, $\rho$ is the density, $v$ is the velocity, $g$ is the gravitational ...
0
votes
2answers
119 views

Why does the critical angle for refraction exist?

When light moves from a medium with a high refraction index to a medium with a low refractory index (water to vacuum), that there exists a "critical angle" at which no more refraction occurs. What is ...
0
votes
1answer
46 views

Planets falling through wormholes

I am writing a story which will use a wormhole of one sort or another as a plot device to put an aliens' planet in our solar system. I'd like to know: How big a wormhole would have to be for tidal ...
-1
votes
2answers
142 views

Most stationary object in the universe

There is an object in the universe for which the Sun appears to be more stationary as it travels through the universe than a star on some other system. There is probably another object for which both ...
1
vote
1answer
140 views

Is max speed of causality (light) proven experimentally?

Is it possible to have an alternative theory which is consistent with experiments supporting GR, but which doesn't mandate a speed limit on causality? In other words, I understand there is ...
7
votes
0answers
106 views

Real world applications of post-1950s High Energy Physics [closed]

Imagine a world where people knew everything we know today except for high energy physics, where their knowledge ends at our ~1950s level. Is there any real world application, any particular piece of ...
0
votes
1answer
61 views

Is there any way to create a globe with gravitational or similar attractive force - earth simulator?

This may sound like a dumb question. Is there anyway to create a miniature version of earth or its gravitational force. A globe or sphere which have force inside it which can attract the things ...
3
votes
0answers
23 views

How does flow rate affect plume dynamics and film properties in PLD?

So I use a home-built Pulsed Laser Deposition(PLD) system to deposit metal oxide thin films. I use a $ 248\ \mathrm{nm KrF}$ laser. I recently deposited two films under slightly different conditions. ...
0
votes
0answers
27 views

Are only measurements registered as events?

When we measure an electron or some other system behaving quantum mechanically, we observe something. Now, this can be called as an event in relativity terms meaning if we live in 1-D spacetime, only ...
2
votes
0answers
81 views

how to analyze the collision of two photons with four-momentum vector? [closed]

Q: If two photons with energies $E_1$ and $E_2$ collide, with their trajectories making an angle $\theta$. Is the following right about individual initial 4-momentums and total initial 4-momentum? and ...
1
vote
2answers
27 views

Using Thermoelectric generator to power another Peltier cooler

i have a feeling that this isnt possible but wanted to double check. Could you use a Peltier plate on a heat source to generate electricity and then use that electricity to power a Peltier plate as ...
1
vote
1answer
63 views

Is there a way to write the Lorentz force in terms of one field, $L$, and one charge, $X$?

I have heard that physicists like to write electromagnetism as one force (the Lorentz force) and define it as $\vec{F_L}\left(q, \vec{v}, \vec{E}, \vec{B}\right) = q\left(\vec{E} + \vec{v} \times \vec{...
2
votes
0answers
27 views

Why are only some materials ferromagnetic? [duplicate]

I've been told in my solid state class, that ferromagnetism occurs when electron spins are alligned. This happens, as I understand it, when it is "energitically favorable" and when the wavefunction is ...
0
votes
1answer
109 views

treat Physical pendulum as point particle

Suppose you have a physical pendulum. When is it possible to approximate the physical pendulum system as a point particle?
0
votes
0answers
46 views

Chemical Thermodynamics - Maxwell Relations

I am trying to derive an expression for the isentropic compressibility in terms of thermal expansion coefficient $\alpha_P$, the isothermal compressibility $\kappa_T$ and the constant pressure heat ...
0
votes
2answers
51 views

What can be the probable escape speed from the event horizon of a black hole?

Is there any approximate escape speed value from the event horizon of a black hole or is it infinite ?

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