Bosons are integer-spin particles that obey Bose-Einstein statistics.

learn more… | top users | synonyms

0
votes
1answer
27 views

Showing phase change for fermions

When discussing identical particles books often use that the states are eigenstates of the permutation operator: $P_{ij}|\psi\rangle = \lambda |\psi\rangle$ for bosons this is easy to see if I use ...
0
votes
0answers
12 views

Capturing superfluid condensation with exact diagonalization

Doing exact diagonalization on bosonic systems is tricky, because the possibility of multiple occupancy means that even the single-site Hilbert space is infinite-dimensional. It's my understanding ...
2
votes
0answers
48 views

Can fermions composing a boson ignore Pauli's principle?

After a discussion with a fellow student, we came above this problem asked as question in the title. A similar question was answered here. But it doesn't answer the question for us. In a BEC, many, ...
6
votes
1answer
46 views

Why does exchanging coordinates produce a phase of $\pm 1$ in an identical particle wavefunction?

Consider a system of two identical particles described by a wavefunction $\psi(x_1, x_2)$. There are two kinds of exchange operators one can define: Physical exchange $P$, i.e. swap the positions of ...
-3
votes
0answers
33 views

Working out range and lifetime of W boson [duplicate]

I am starting to study A-Level physics and I would like to have some help with this question, as I got no clue how to answer it: State the approximate range of W boson and estimate it's lifetime, ...
12
votes
2answers
332 views

Combining two finite number fock spaces into one

Say I have two separate systems of identical Bosons, one with N Bosons the other with M. System one is described by a state $|\psi_1\rangle$ the other with $|\psi_2 \rangle$ which are expressed in a ...
-5
votes
2answers
51 views

Clarification of the concept of Boson Mediator and 'Mediation' in Physics? [closed]

I would like to have a clear concept of Higgs 'mediator' and that 'mediation' speak in physics, what you 'swap' a particle with ...
1
vote
0answers
217 views

What does the “protophobic fifth force” imply?

There is a recent paper on arxiv http://arxiv.org/pdf/1604.07411v1.pdf and prl http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.116.042501 It seems that the authors found the fifth force. ...
7
votes
4answers
253 views

Why don't we call the fermions in the standard model force carriers?

Maybe this is a chicken-and-egg problem, but couldn't we call all the bosons fundamental and treat the fermions as force carriers between them? EDIT: After all we never see the asymptotic states of ...
3
votes
1answer
57 views
0
votes
0answers
60 views

What is more fundamental $E=\hbar \omega$ or $E=c\hbar k$?

Let us say I have a massless particle (not necessarily a photon) then in a medium where $\omega \ne c k$ (e.g. a dispersive medium) what is the energy of the particle? As my title indicates are think ...
3
votes
1answer
71 views

Stern-Gerlach experiment with Bosons

I'm new to this forum and I'm studying semiconductor physics at the moment. I just wanted to ask a thing about the concept of spin: when it was studied for the first time, in the Stern-Gerlach ...
5
votes
1answer
49 views

Super conductivity and energy gap in fermionic/bosonic subspaces

I am trying to understand the phenomena of super-conductivity from a broader level. What I understand for now is that for super-conductivity to be possible in a system, a necessary requirement is that ...
0
votes
0answers
26 views

What is the difference between the generation of mass for Fermions compared with Bosons in the standard model?

I've seen a few questions asking how the Higgs mechanism generates mass for particles of the standard model. However, I haven't seen any which specify the differences between Bosons and Fermions in ...
9
votes
4answers
5k views

How do particles become entangled?

A person asked me this and I'm just a lowly physical chemist. I used a classical analogy (how good or bad is this and how to fix?) Basically, light has a net angular momentum of zero, insofar as ...
0
votes
1answer
34 views

How to determine the direction of arrow on Feynman diagram for $W$ boson line?

I am somewhat confused. Looking through these slides (especially the 11th), which show Feynman diagrams involving $W$-bosons, I can't figure out which way to draw the arrow near the $W$ boson? How do ...
1
vote
2answers
37 views

Inverting density in favour of fugacity

In these notes on pages 80 and 81 the following step was used The density in terms of fugacity is $$ \frac{N}{V} = \frac{z}{\lambda^3}\left ( 1+ \frac{z}{2 \sqrt{2}} + \ldots \right ) $$ and this ...
9
votes
3answers
2k views

Is there a reason why the spin of particles is integer or half integer instead of, say, even and odd?

It seems to me that we could change all the current spin values of particles by multiplying them by two. Then we could describe Bosons as even spin particles and Fermions as odd spin particles. Is ...
0
votes
0answers
47 views

Quick clarification needed on degeneracy

I need some hints about degeneracy. So, I consider an energy level degenerate if there are two distinct wave functions at that energy. Then, let's say I have two spin1/2 fermions in a 1D box. Is ...
0
votes
2answers
31 views

Exchange principle in terms of states and coordinates?

I have seen the exchange principle written in two ways, one in terms of coordinates and the other in terms of states: If $\psi_{AB}(1,2)$ represents particle $A$ in state $1$ and particle $B$ in ...
2
votes
0answers
85 views

Why do we need to suppose the chemical potential is zero in this situation?

I've been working on some statistical mechanics problems and one of them asks to compute the pressure with chemical potential zero of a boson gas whose particles do not interact and whose energies are ...
1
vote
2answers
108 views

Charge operator and the Goldstone boson

Can you explain a one question from Goldstone theorem about charge operator, what does it mean when theory said that charge operator annihilate vacuum and even it create new state of vacuum, which is ...
4
votes
0answers
74 views

Physical interpretation of the chemical potential in Bose and Fermionic gas

I understand that both Fermions and bosons have the chemical potential $\nu <0$ when it is T>0, but still behave classically, the fermions would increase its chemical potential at T=0, whereas the ...
0
votes
2answers
132 views

Why $\delta F = B\epsilon$ and not $F=B \epsilon$ in supersymmetry?

We can express supersymmetric transformations as $$\delta F = B\epsilon, \tag{1} $$ $$\delta B = F\bar{\epsilon},\tag{2}$$ where $B$ and $F$ denote the bosons and fermions, respectively, in the theory ...
5
votes
2answers
397 views

Bose Enhancement Factor

How may one explain the fact that the probability of a boson transferring to a state with an occupation number n is 'enhanced' by a factor of (1+n), compared to the classical case? (In the classical ...
3
votes
0answers
84 views

The mass of X Boson (and Y Boson too)

I was reading an article on Wikipedia about the hypothetical particles called $X$ and $Y$ Bosons. Looking at their "calculated" masses, I felt quite weirded. Their mass should be $$m = 10^{15}\ GeV/...
1
vote
1answer
55 views

Can we measure the energy of one of several identical particles?

Suppose we have a many-particle system described via a many-particle wavefunction that involves single-particle states $\lvert\lambda_{a}\rangle$, $\lvert\lambda_{b}\rangle$, $\lvert\lambda_{c}\rangle$...
0
votes
1answer
38 views

Unitary Bose gas

A unitary Bose gas (more about it [here]) is defined to occur when the scattering length diverges. What I don't understand, however, is which quantity/matrix is actually unitary? I mean, they could ...
3
votes
3answers
257 views

Perturbative series for bosons

I have recently read that ... the perturbation series ... is valid only when the perturbed state is qualitatively similar to (or ‘has the same symmetry as’) the unperturbed state. This means ...
0
votes
2answers
60 views

Can both types of W boson be responsible for a neutron-neutrino interaction?

My textbooks lists the exchange particle for a neutron-neutrino interaction as being the W- boson. Is this the only option, or can it also be a W+ boson? Nothing jumps out at me that would suggest it ...
0
votes
1answer
49 views

Bosonic qubits using BEC versus usual qubit implementations based on energy levels

All condensate atoms in a BEC (say like Rb, etc) effectively occupy the lowest energy-state. If it is that the case, then how are such bosons in a BEC encoded as a qubit? In particular, when Grover ...
2
votes
2answers
339 views

What is meant by fermionic and bosonic “modes”?

The paper The Dirac quantum automaton: a short review (pdf) starts off by stating: The starting point for the construction of space–time and the physical laws therein is an unstructured, countably ...
0
votes
2answers
50 views

Two stones (bosons) in one place

A macroscopic object (let's call it "stone") may incidentally be a boson, right? But identical bosons are "allowed" to have the same quantum state. From this I conclude that two identical stones may ...
-1
votes
1answer
63 views

Why do bosons and fermions exist? [duplicate]

if i have two particles in states: |1> and |2> respectavly , and they are not identical then the combined state is |1>|2> , but if they are identical then the labels 1 or 2 are arbitrary and could be ...
-1
votes
1answer
76 views

What are the differences among bosons, force-carrier particles and mediators? [closed]

Are all bosons force-carrier particles? What is the difference between these three concept? Where can I find a comprehensive & detailed information about these particles? How it can be related ...
0
votes
0answers
28 views

quantum two particle system? [duplicate]

according to wiki if you have two different particle with state vectors |1> and |2> respectively than the state vectors of the combined system is the tensor product denoted: |1>|2> but if the two ...
2
votes
1answer
126 views

Examples for p-form gauge fields [closed]

I don't completely understand the notion "p-form". Can you give me examples of 1-form, 2-form and 3-form gauge fields? What kind of p-form is e.g. the Higgs field, the electromagnetic four-potential, ...
-1
votes
1answer
105 views

Is this a good argument against time travel? [closed]

Two fermions in two different points of space cannot be made to exist in the same point of space. It follows then that two fermions in two different times cannot be made to exist in the same time. ...
0
votes
1answer
38 views

Is there any sense in which mesons could act as force carriers, in the way that gauge bosons do?

Gauge bosons are force carriers. Mesons are composite bosons and have similar characteristics to gauge bosons. Is there any sense in which mesons could act as force carriers?
4
votes
6answers
652 views

Fermion vs. Bosons and particle vs. wave: is there a link?

I'm puzzled since several years on this basic aspect of quantum mechanics. Quantum theory is supposed to describe particle-wave symmetry of our world. It also describes our universe in term of bosons ...
1
vote
1answer
57 views

Identical particles: Why only two possibilities?

Given two identical particles, Wikipedia says that the wavefunction of a combined system where the first particle is in state $|n_1\rangle$ and the other one is in $|n_2\rangle$ is $|\psi\rangle=|n_1\...
0
votes
0answers
125 views

Path integral for boson vs fermion (soft derivation + use )

I have been looking around for a soft derivation with a bit of detail for boson and fermion path integrals that I could understand. I have a passing knowledge generally of what a path integral is in ...
0
votes
0answers
36 views

What does the particle to volume density physically mean for Bose-Eisenstein condensate?

The average number of particles $\langle N\rangle$ for a Bose-Eisenstein condensate in 3D is given as $$ \dfrac{\langle N\rangle}{V} = \dfrac{V^{-1}}{e^{\beta (0-\mu)}-1} + \int_{0}^{\infty} \dfrac{V^{...
2
votes
1answer
49 views

Mass eigenstates and occupied physical volume?

I recently read about atom lasers and it made me wonder about something I recalled from my limited experience with quantum (two undergraduate and two graduate level classes). I recall that some ...
2
votes
0answers
47 views

Do we expect to find a dark energy boson?

Is dark energy expected to be a force carrying particle that interacts with all forms of matter?
0
votes
0answers
131 views

Charge conjugation of particle and anti particle system

I've seen in the literature that quark and anti-quark (or in general, fermion and anti-fermion) bound states, such as the neutral pion or positronium, have C eigenvalue of (-1)^(L+S), where L is their ...
0
votes
2answers
144 views

Massless bosons but not massless fermions?

I noticed some article on massless Weyl fermions and it got me thinking. I'm wondering if there is any explanation for why bosons (specifically gauge bosons) can be massless (photon and gluon) but we ...
9
votes
2answers
574 views

Is electric charge truly conserved for bosonic matter?

Even before quantization, charged bosonic fields exhibit a certain "self-interaction". The body of this post demonstrates this fact, and the last paragraph asks the question. Notation/ Lagrangians ...
6
votes
4answers
7k views

Meaning of the chemical potential for a boson gas

My lecturer told me that the mu is the Chemical potential is zero or negative, in the following example, mathematically it acts as a Normalisation constant. But is there any Physical insight about why ...
2
votes
1answer
108 views

systems of particles that are not symmetric or anti-symmetric; Helium 4

Suppose I have an electron and a proton, and that the electron is in the spin-up state, and that the proton is in the spin-down state. The particles are distinguishable, so I should just be able to ...