1
vote
0answers
45 views

Where did the higgs field energy go when it broke symmetry

Where did the Higgs field energy go when it broke symmetry and fell into its ground state. If it did that in the whole universe huge amounts of energy must've been released.
0
votes
0answers
54 views

Specific Heat of Liquid Helium

At the lambda point, the specific heat of Liquid Helium diverges. After searching for a curve, I've found only measured curves. Is there a theoretical curve for this transition?
0
votes
0answers
26 views

What's the difference between cosmic time and conformal time? [duplicate]

When they say that the age of the Universe is about 13.7 billion years, they are giving the age in cosmic time, is that right?. There's this other thing called conformal time which I don't understand. ...
0
votes
0answers
105 views

Why are hockey pucks so indestructible?

After watching a hockey puck be exposed to extreme heat as well as extreme cold, the puck seems to end up in pretty good shape. I can sort of understand the puck vs. hot ball of nickel since the area ...
1
vote
1answer
43 views

Transformations of electroweak gauge field $W_\mu$ under $U(1)_{e.m.}$

As the vector boson field $W_\mu$ is, together with $Z^0$, the gauge field for the Standard electroweak model, I know it transforms as a connection under the $SU(2)\times U(1)_Y$ group. But, when this ...
0
votes
1answer
74 views

What happens at lambda point?

When Boson gas approach lambda point (no matter from superfluid side or liquid side),the heat capacity tend to diverge, doesn't this mean that we can never drive the gas through lambda point?(cause we ...
1
vote
1answer
127 views

Is it dangerous to use the water tap/bathe/shower during a thunderstorm?

As the title says, is there any danger in touching the water tap or sitting in a bath tub etc. inside the house during a thunderstorm? I heard that it is dangerous, as the lightning could hit some ...
8
votes
2answers
2k views

Is the Earth the center of the Solar System? [duplicate]

Alright guys, so I attracted you with the title. Now, to preface the question, I am fully aware of the work of Copernicus, as well as the concepts of Heliocentrism and Barycentric Coordinates. I have ...
0
votes
2answers
200 views

Two masses attached to a fixed vertical spring

The problem statement, all variables and given/known data Two mass-less springs with spring constant k = 1000 N/m each have 1 block attached (Spring A is fixed to the ceiling and is attached to ...
1
vote
1answer
42 views

Is the first excited state of a superconducting qubit a stationary state?

A superconducting qubit is essentially an anharmonic oscillator with uneven spacings of the eigenstates. These states are eigenstates of the overall hamiltonian, which should mean that it is an energy ...
0
votes
1answer
60 views

Can infrared lasers still do damage to things if they are powerful enough?

So I get that infrared light is not visible to the human eye without some sort of device to assist in helping you see it, but I was just wondering how that plays into things like lasers. I know you ...
0
votes
2answers
76 views

The notion of fixing a gauge

I don't understand the notion of gauge fixing; can we choose any gauge or are there some restrictions? For example why can we choose $\nabla\phi = 0$ here: Determine the Electric field using ...
2
votes
0answers
33 views

What instruments are used to determine the degree of water in the atmosphere of Mars?

More precisely, how does one go about measuring the small amount of water vapor in what is almost a vacuum by terrestrial standards?
0
votes
1answer
53 views

Creation and annhilation operator in the Heisenberg picture

I am trying to calculate the time evolution of the creation/anni. operator in the Heisenber picture. On this webpage http://quantummechanics.ucsd.edu/ph130a/130_notes/node191.html, they used the ...
0
votes
0answers
1k views

Relationship between phase velocity and group velocity with De Broglie postulates

If I have to show that the group velocity of a free particle is twice the phase velocity, is the following argument correct (avoiding to use the wave function and the momentum operator): For a ...
0
votes
1answer
141 views

Probability density for momentum in Quantum Mechanics

In a book i found the following equations: $$ \phi(k)=\frac{1}{\sqrt{2\pi}} \int_{-\infty}^\infty \Psi(x,0)e^{-ikx}dx $$ and $$ \Psi(x,t)=\frac{1}{\sqrt{2\pi}} \int_{-\infty}^\infty ...
3
votes
1answer
127 views

Interacting fermions on a lattice

My rough understanding about lattice simulations of bosonic quantum field theories is that the partition function can be approximated by explicitly summing over a large number of field configurations, ...
0
votes
0answers
61 views

Determine the Electric field using magnetic vector potential

How to determine $\vec{E}(t)$ form the magnetic vector potential ? when $\vec{B} = \frac{\mu_0i(t)}{2\pi r}\vec{e_\phi}$ is the magnetic field at the point given by : $M(r,\phi,z)$ ( cylindrical ...
6
votes
4answers
114 views

Energy conservation without action principle?

The normal tagline for energy conservation is that it's a conserved quantity associated to time-translation invariance. I understand how this works for theories coming from a Lagrangian, and that this ...
0
votes
0answers
67 views

How to calculate magnetic flux density in gap

I have the following setup (where the relative permeability of the ring is $\mu_{r}$): I am struggling to work out how to calculate the magnetic flux density $\vec{B}$ in the gap in the ...
0
votes
2answers
126 views

Gauss law for gravitational field

Gauss's law is fundamental law of electrostatics. But Can we apply Gauss's law for Gravitational field also?
2
votes
1answer
128 views

Parent hamiltonian of AKLT state

Given a translationally invariant Matrix Product State (assuming periodic boundary condition) on $N$ sites of dimension $d$ each, which takes the form $\sum_{i_1,i_2\ldots ...
1
vote
0answers
91 views

Ampere's law and magnetic circuit

For magnetic circuit there is an equation NI=HL. This equation is obtained by applying Ampere's law. H is magnetic field intensity and L is the length of the circuit. In following picture the equation ...
0
votes
2answers
219 views

Get coefficient of friction given mass, forward force, and acceleration?

I'm aware that this is extremely basic but I've forgotten how to get the coefficient of friction when given a forward force and acceleration. Can someone describe to me the algorithm for solving the ...
1
vote
2answers
102 views

Find the covariant metric tensor from a given contravariant metric tensor

If given $$g^{\mu\nu}=\pmatrix{\begin{matrix} 1 & 0 & 0 & 0 \\ 0 & -1 & 0 & 0 \\ 0 & 0 & -1 & 0 \\ 0 & 0 & 0 & -1 \\ ...
4
votes
1answer
81 views

Why is $U(1)$ special when defining global charges?

For gauge groups like $SU(2)$ and $SU(3)$ etc. we know that observable states such as mesons or baryons must be charge neutral. However, for a $U(1)$ gauge group we can have charged initial states in ...
0
votes
1answer
21 views

Ground state energy of Bose Einstein gas

I am wondering why BE gas ground state contribute no energy.if so, then dose it mean that if we drive the Bose gas to absolute zero,then it doesn't own any energy?
1
vote
1answer
66 views

Experimental evidence of two neutrinos in muon decay?

We know that the pion decays into a lepton/neutrino pair while the muon decays into a muon neutrino, electron and electron neutrino. How do we distinguish them experimentally? Would the muon decay ...
0
votes
0answers
27 views

Decay chain governed by first long-lived particle?

Suppose we have a decay chain reaction A->B->C-> ....Z Why is it a good assumption that the decay rate of all species in the chain is governed by the rate of the first long-lived one? Suppose B -> C ...
1
vote
1answer
59 views

Log of a quantity and graphs in log-scale

Is there any difference between taking the logarithm of a quantity, and plotting a quantity in logarithmic scale?
7
votes
1answer
108 views

What is the heaviest stable element in the center of the sun due to Photodisintegration?

Source that got me curious (page 5): http://astro1.physics.utoledo.edu/~megeath/ph6820/lecture27_ph6820.pdf High energy photons can cause larger, less stable elements to undergo fission. Uranium ...
1
vote
1answer
86 views

What is the acceleration due to Earth's rotational and orbital movements?

What are the accelerations due to earths spin and orbital motion around the sun? It must be negligible otherwise humans would have been feeling it, are there any instruments that can measure it? would ...
2
votes
1answer
139 views

Is there any other superfluid element except helium?

Is there any other superfluid element except helium? Everywhere we see and speak about superfluidity, we just speak about superfluid helium. but is't there any other element or material or system ...
1
vote
1answer
71 views

Why is the elemental volume of a sphere equal to $4 \pi r^2dr$?

I was doing this question on calculating the electric field at a certain point in a sphere (length $r$ away from the centre), where the charge density is given by an equation. When I checked the ...
0
votes
1answer
42 views

Part/Object Geometry

Given Inertia Tensor, Principal axes vectors, Center of Gravity, and the Moments. Is it possible to obtain object/part dimensions?
0
votes
0answers
49 views

Expansion of solids on heating

I read that when we heat a solid, it expands! Based on circumstances it can expand in area, length and volume! My question is , that do they expand to a certain extent or keep on expanding, if we ...
0
votes
0answers
50 views

Differences between empiric laws of Galileo and Kepler

Although in both cases we encounter empiric laws, as far as I know Galileo's laws of motion differ in some way from Kepler's laws of planetary movements. In what way?
0
votes
1answer
41 views

How to write magnetic dipole transition hamiltonian using ladder operator?

The magnetic dipole transition Hamiltonian is $\hat{H}=\frac{e}{2m_ec}\hat{\mathbf{B}}\cdot\hat{\mathbf{L}}$ How do I express it in terms of ladder operator $\hat{L}_+$, $\hat{L}_-$, and the ...
2
votes
0answers
35 views

Mermin Inequality

Suppose I want to calculate the maximum of Bell inequality for three parties system. In this case I will have 6 measurement directions (unit vectors). It has been done in the paper PHYSICAL REVIEW A ...
0
votes
0answers
17 views

Why can't our universe be spherical? [duplicate]

if we happen to follow the bigbang singularity hypothesis, when he explosion occured shouldn't it expand in all directions. Seemingly our universe shouldn't have any boundaries. I searched for the ...
0
votes
1answer
87 views

Why are we not able to visualize Dimensions beyond 3 (or maximum 4 including time)?

We consciously know and feel the first three dimensions and with some thinking time as well. But according to literature like String theory etc., we have many many more dimensions. We can readily ...
1
vote
0answers
47 views

Normal coordinates for harmonic approximation (classical lattice vibration)

I am reading Jenő Sólyom's "Fundamentals of the Physcs of Solids" vol. 1. and i am very much stuck at this point (chapter 11.3.2 in the book): In the harmonic approximation the potential energy of a ...
0
votes
1answer
30 views

Electrostatic potential due to two charge system

When we calculate electric potential energy of a two particle system, say first I bring $+q_1$ and then I bring $+q_2$ against $q_1$'s electric field. Say I get that $q_2$ charge to a point $r$ ...
0
votes
1answer
154 views

Bead on a rotating wire - Conservation of angular momentum, fix points

Lets consider a wire in the x-y plane which rotates with constant angular velocity $\omega$. The coordinates of a bead, which is forced to stay on this wire, can then be expressed as $$x=r \cos(\phi) ...
0
votes
0answers
55 views

Is the Big Bang notion compatible with the flat space? (A problem with the **moment** of Big Bang, not with the place of it) [duplicate]

A passage from a paper: "If one imagines running the clock backward in time, any given region of the universe shrinks and all galaxies in it get closer and closer until they smash together in ...
0
votes
1answer
82 views

Is it better to walk or run when there is rain? [duplicate]

When I was coming from school to my house, there was heavy rain. Then one of my friends said "Don't simply walk, run fast". Then the question came to my mind: how should I go so as to avoid wetting: ...
1
vote
2answers
128 views

Can pressure be negative? [duplicate]

From Wiki and from physics fundamentals lections I received info that pressure is scalar value. But in definition you have relation between projections of two vector values to normal axe-force and ...
-2
votes
2answers
97 views

The physics of tripping on a stone [closed]

You know, you are walking or running at a certain velocity, your foot gets stuck on an obstacle and you end up flat-faced to the ground. What is the physics behind it? How does the linear motion ...
2
votes
3answers
206 views

Why doesn't a global frame of reference exist for GR?

I only have at best a layperson's familiarity with GR, so forgive me if I am asking a basic question, but I have heard that in GR, we cannot have a global frame of reference, that is a frame of ...
1
vote
1answer
117 views

Explanation of van der Waals force

Can someone please explain why the van der Waals force is attractive instead of repulsive? My understanding is that is has to do with the electron cloud creating a dipole, but I can't seem to ...

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