0
votes
0answers
4 views

Different postulates and statistical interpreations of quantum mechanics

Hi I have a query about the difference of two aspects of the statistical interpretation of quantum mechanics given in the popular introductory quantum mechanics books "Introduction to Quantum ...
0
votes
0answers
2 views

How does electrical energy develop by concentrating ions on one side of a biomembrane?

In biology there is a topic called oxidative phosphorylation. In the first step of this process substrates such as isocitrate is oxidised and the electrons are transferred to coenzymes NAD+ or FAD ...
0
votes
0answers
2 views

Tractrix - velocity pointing to pulling point

It is said the tractrix is the curve described by a mass being pulled by a string, where the end of the string being pulled moves with constant speed, and the mass suffers a drag force. What is the ...
1
vote
0answers
15 views

Integrating out heavy fields while preserving symmetries

The basic a-b-c for integrating out heavy fields what one learns when making the example of Fermi theory, is that if you have a Lagrangian $L= -\frac{1}{4}F^{\mu\nu}F_{\mu\nu}+\frac{1}{2}M^2 V^\mu ...
0
votes
0answers
7 views

On Carnot engine and heat pollution

Suppose a power plant uses a Carnot engine to generate electricity, using the atmosphere at 300 K as the low-temperature reservoir. Suppose the power plant produces 1 × 106 J of electricity with ...
-1
votes
1answer
14 views

Global Hyperbolicity in spacetime Manifold

If space time is timelike or null geodesically incomplete but cannot be embedded in a larger spacetime then we say that it has singularity. What does incompleteness means here?
-1
votes
2answers
23 views

What is more basic thing to explain phenomenons : Energy or Force?

You know many physical happening are explained by considering forces or we can explain these phenomenon using energy (like energy conservation, etc.). so i was wondering that explaining the physical ...
1
vote
0answers
11 views

Very precise calculation of the heliocentric position coords (X, Y, Z) the point of coordinates (N/S, W/E degrees) on Earth

I need a very precise calculation of the heliocentric position coords (X, Y, Z) the point of coordinates (N/S, W/E degrees) on Earth. Currently, thanks to the algorithm which generates the position ...
-3
votes
0answers
14 views

Books for students [duplicate]

Can any one please suggest me books for physics. I need a book for good theory and concept . And a book for practice , it should contain some solved questions. The both the books should contain ...
1
vote
0answers
8 views

What is exactly the difference between an active and passive frequency standard?

In the case of passive atomic frequency standard, we take an atomic reference which has a resonant frequency response centered at certain particular frequency. Then we take a local oscillator and tune ...
1
vote
0answers
17 views

What to do when the fields are arranged in a matrix?

I am dealing with a Lagrangian in which the fields are arranged in an $N\times N$ matrix and i have to find the minima of the potential. Usually i would write the Lagrangian in components and then ...
-2
votes
0answers
13 views

Mathematical formula for maximum sound pressure level [on hold]

I googled a math equation for calculating Maximum Sound Pressure Level but couldn't help myself. What is it?
0
votes
1answer
31 views

Scattering in Schrödinger picture

If we look at a scattering process in the Schrödinger picture for a Hamiltonian $H = H_0(t) + V(t)$ where $H$ is independent of time (because we examine a theoretical situation after accelerating ...
0
votes
1answer
29 views

Are pure Dirac fermions (electrons, quarks, …) allowed to have effective Majorana mass?

Charged particles such as electrons and quarks are not allowed to have a hard Majorana mass (see here). With 'hard' I mean an explicit mass term in the Lagrangian which would break the corresponding ...
11
votes
3answers
319 views

Why does LIGO do blind data injections but not the LHC?

The LIGO group has a team that periodically produces fake data indicating a possible gravitational wave without informing the analysts. A friend of mine who works on LHC data analysis told me that ...
0
votes
0answers
21 views

Noether current for a transformation for the Klein-Gordon Lagrangian

I have this Lagrangian density $$\mathcal{L} = \frac{1}{2}(g^{\mu\nu}\partial_\mu\phi\partial_\nu\phi^* - \mu_0^2\phi^*\phi)$$ with $g_{\mu\nu} = g_{\mu\nu}(x^\alpha)$ and I need to get the Noether ...
-2
votes
0answers
30 views

Eigenvalue equation with position operator

I have done a little run through of a basic QM eigenvalue equation for a particle on a 2D plane from bra-ket notation in the spirit of a complex position operator, although I have solved the SE, ...
0
votes
4answers
25 views

How to find electric potential from electric field? [on hold]

How to find potential difference when electric field is given ?
0
votes
0answers
8 views

does changing air velocity change the frequency of sound coming out of a whistle?

If I use an air compressor and vary the velocity of the air coming out, does the frequency of the whistle change too?
0
votes
1answer
16 views

Thawing of permafrost causes positive feedback loop in greenhouse effect?

This is claimed in my climate change class, which is admittedly pretty sparse in rigorous climate physics. The reason is that there are pretty large carbon deposits in glaciers which will further the ...
1
vote
0answers
24 views

World's Largest Radio Telesope : How accurately does it need to be figured?

In Guizhou Province, China, the worlds largest radio telescope is almost complete, measuring 500 metres across. I am aware that todays largest optical telescope require very accurate figuring and ...
0
votes
0answers
18 views

Is the magnetic field caused by the lenght contraction, as seen by us, in the frame of a fast moving charged particle?

If for example an electron moves very fast relative to us, then the length contraction as seen by us, causes the electric field lines to compress themselves in the direction of motion. Is this the ...
-1
votes
0answers
19 views

Is the change in viscocity of water at 1C vs 99C discernable visually?

Waters viscosity varies from 1.7 at 0C to .3 at 100C. Is this visually confirmable?
0
votes
0answers
15 views

Can a Van de Graaff Generator be used to put plasma at high potential?

Lets say hypothetically, we use a sphere of plasma (ofcourse lab-plasma, stabilized somehow) instead of a sphere of metal in a van de graaff generator. Now can we use it to put a large amount of ...
0
votes
0answers
19 views

High School Physics What to Do [duplicate]

I am an aspiring physicist in high school and I would like to know ways to get involved. Of course, it would look great for potential physics colleges, but I really want to understand physics better. ...
1
vote
1answer
50 views

Why is Wick contraction a $c$-number?

It is mentioned in Fetter's Quantum Theory of Many-Particle Systems (in contraction part of section 8 Wick's Theorem), that: contractions are c numbers in the occupation-number Hilbert space, not ...
-1
votes
0answers
15 views

Does closing the shades at night make the room brighter?

Does closing the shades at night make the room brighter? Is the light kept in, or is the dark kept out?
0
votes
2answers
36 views

Why does the centrifugal term involve a vector originating from the center of Earth?

Why in every mechanics/dynamics book I look the centrifugal force due to Earth's rotation is measured from "the center of Earth"? For example in Marion's dynamics, the fixed inertial axes are placed ...
0
votes
0answers
7 views

Hot Water fountain experiment with mohr pipette

Why does water shoot out the tip of a Mohr pipette when half filled with hot water and turned upside down?
3
votes
1answer
47 views

Schrödinger-Pauli Equation Solutions

The Schrödinger-Pauli equation is the non-relativistic limit of the Dirac equation, and therefore describes spin-1/2 particles in an external electromagnetic field. It is given by: ...
1
vote
1answer
20 views

What is the gravitational/electric/inverse-square field inside a cylinder?

I've read from the shell theorem that an inverse-square potential has zero field inside a spherical shell. What about the field inside a cylinder? Are objects inside a long cylinder attracted to the ...
1
vote
0answers
14 views

Multi-center Taub-NUT geometry and homologically nontrivial cycles

In the string theory book by Ibanez and Uranga (click here for the Google books excerpt), the four-dimensional multi-center Taub-NUT metric is written as $$ds^2 = \frac{V(\textbf{x})}{4}d\textbf{x}^2 ...
7
votes
3answers
947 views

If water is essentially incompressible, why are there tides?

So recently we were taught in school that tides are formed because the moon 'cancels out' some of the earth's gravity, and so the water rises because of the weaker force. But if water is not ...
-3
votes
1answer
41 views

What is hyperbolic metamaterial?

What is hyperbolic metamaterial? Could you explain in a few words what is hyperbolic metamaterial?
0
votes
0answers
13 views

What is/are the resonant frequencies of a closed liquid cylndrical jar

My general question is how to calculate (via a formula) the resonant frequency of a cylindrical jar containing a liquid, assuming the speed of sound of that liquid is known and the solid material If ...
-3
votes
1answer
65 views

Why fall bombs always in a horizontal position? [on hold]

I´m not sure but it seems to me when bombs are dropped they always fall in a horizontal position. Which is to say, not with their nose down. What´s the reason for this?
-3
votes
0answers
16 views

What are the forces generated by a powered angle grinder?

I was wondering what forces come from a powered angle grinder. Given the fact that a angle grinder is not just a spinning disk, but also a grip containing the motor and mechanics i wanted to know how ...
4
votes
0answers
50 views

The Madelung Equations are Euler Equations for Quantum Mechanics. What is the Lagrangian description of Quantum Hydrodynamics?

The Madelung Equations of Quantum Mechanics suggest the Hydrodynamic Model of Quantum Mechanics (Quantum Mechanics is described as a fluid of universes in a multiverse, which, in the non-relativistic ...
0
votes
0answers
46 views

Mystery $p^0$ particle

Some exercises in my physics book mention a particle denoted $p^0$, but I can't seem to find any information about this particle, neither in my book nor on the web. I've been able to deduce from the ...
-3
votes
1answer
22 views

Data transmission in optical fibers

Im reading though my Network Architecture lecture notes and it states optical fibers need a repeater every >10km. Repeaters are used to amplify digital signals but the notes do not explain or state ...
-4
votes
0answers
28 views

Earth mass redistribution

Knowing we haven't imported construction materials from space has mankind altered the earth's weight through time due to building work? Or will it remain constant?
-3
votes
0answers
18 views

A question about glossy paint

Once I made drip paintings, that made themselves. I dropped an amount of glossy paint on a carton, and one time a piece of paper fell on the drying paint. When I came home I pulled off carefully the ...
1
vote
1answer
48 views

Relativistic Rocket Fuel Requirements

I am trying to reconcile two different calculations of fuel for a 1g constant acceleration/deceleration trip to Alpha Centauri. One found here ...
1
vote
1answer
18 views

Thermal equilibrium - magnetization

The electronic ground state of neutral sodium atoms in a magnetic field splits into two no longer degenerate energy states. In the thermal equilibrium the occupation probability of the states is ...
-2
votes
1answer
22 views

What is The force a body exerts on a vertical circular track?

I am trying to calculate the force a body exerts on a vertical circular track with no friction at its highest point I know the centripetal force at that point is mg and the given data is the velocity ...
0
votes
0answers
6 views

2D slab model for LJ potential

I have a program implementing a LJ(Lennard-Jones) molecular Dynamics(MD) simulation with isokinetic thermostat. I want to modify that program to study the phase characteristics of LJ particlesin 2D ...
-1
votes
1answer
16 views

Current flow in absence of a potential difference

What if at two different points in a wire connected to a system of capacitors and resistors, the electric potential is equal. Will the current flow? There is also a battery connected.
0
votes
2answers
19 views

Molar Specific Heat Definitions for Gases

In most textbooks, the molar specific heat of a gas is defined for gases at constant volume and constant pressure as follows : $C_v = \frac{Q}{n\Delta T} = \frac{\Delta U}{n \Delta T}$ $C_p = ...
1
vote
3answers
54 views

Does a gluon have mass or not?

I was under the impression that gluons had no mass. Then Wikipedia throws this curveball: "Mass: 0 (theoretical value) < 0.0002 eV/c2 (experimental limit)" Which one should a poor soul go by?! ...
0
votes
1answer
22 views

Force between the plates of a capacitor

As we know that the electric field between two parallel plates of a capacitor is $$E=\frac{\sigma}{\epsilon_0}$$, so the magnitude of force exerted by one plate on the other should have been $$F=QE$$. ...

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