Creation Definition and 323 Threads

If space is expanding and at the same time speeding up, something must be driving it. It also appears to be self perpetuating, as something cannot continue to expand, speed up and backfill at the same time? Could the driving force be dark matter/energy?

Homework Statement Two photon (wavelengths 1pm, 2pm) collide, decaying into a pair positron-electron find the velocities of these particles Everything happens in the x axisHomework Equations The system hc(1*1012+0.5*1012)=E++E- h(1*1012-0.5*1012)=P+-P- E=sqrt(c2P2+m2c4)The Attempt at a Solution...

When a particle and antiparticle pair is created are they created on the same position? If they weren't in the same position it would lead a problem on energy conservation, but they are fermions so they shouldn't be on the same position in space.

Recently I've come across Alexander Vilenkin paper . I can't seem to find the 1988 version so if you can help me with that I would appreciate it. I have 2 basic questions: 1)Am I right in saying that the "nothing" in this paper is not the "philosophical nothing" as in no thing at all ? From...

I have a question about mathematics at the research level. How difficult is it to formulate new open problems in mathematics? For example, can a master's student create such problems? And a doctoral student? Or are only experienced mathematicians able to do this? Does this depend on the research...

Hey all! I'm new to Physics Forums. I'm going through Hawking's famous 1975 paper "Particle Creation by Black Holes" which presents the phenomenon later known as Hawking radiation. I'm going through it for the sake of my own learning and benefit since the paper is a bit ahead of my edge as a...

What I'm about to ask might sound dumb because I'm in sec 3 and just really recently started learning about energy , matter and whatnot. This is really just a pitch To create free energy couldn't you take a really big object and split an atom from a molecule and have it gravitate around that big...

hello! I would like to know: how did the universe create itself from nothing? I'm a novice in a physics so maybe it's not a good question thank you babbane9

Hi guys, I have one question or maybe some questions about creation an optical system. I have a drawing of the system (see below) where are placed 2 right angle prisms. The aim of this is to reflect image from "A" to "B". I suppose that I will need to add some lenses to do it right without...

Yesterday, I attended the following presentation by Prof. Andrea Ghez. https://www.meetup.com/physicists/events/236886090/?gj=co2&rv=co2 In the Q&A session towards the end, there was a question she fumbled to give a proper answer. She mentioned that as long as the mass is compressed into...

I am having difficulty thinking through how a ferromagnetic substance is permanently magnetized. I think I understand that when for example a sample of iron is heated above it curie temperature and then exposed to an external magnetic field , the sample will become permanently magnetized. The...

I understand that one way of creating quantum entangled electrons is by splitting a Cooper pair. Is then their spin property used in the measurement, as this must always sum to ##0## for a Cooper pair? If that is the case, do quantum entangled electrons only exist in the singlet state, where the...

In Quantum Field Theory by Lancaster, equation 3.14 $$ [\hat{a_i},\hat{a_j}^\dagger]=\delta{ij}$$ is introduced as "we define". Yes, example 2.1, where the creation and annihilation operators applied to harmonic operator states, there is a nice simple proof that this is true (although...

I'm trying to check if Ehrenfest theorem is satisfied for this wave function, |Y>=(1/sqrt(2))*(|1>+|3>), where |1> and |3> are the ground and 1st exited state wave functions of a half harmonic oscillator. When I'm calculating the expectation values of x and p using annihilation creation...

Hello PF, This question has been in my head for a long time. Imagine i made a discovery or a theory or a machine ... i don't know just anything that's huge in value. Now if i wanted to seek help to continue it or to develop it , what could stop the person that is helping me from stealing it?

You have probably all heard about magnetic monopoles creation ,but I just want to ask is there theoretical basis (without denying already proven theories) which would allow us to expect natural magnetic monopoles discovery? https://arxiv.org/abs/1607.07460...

The Dalton's atomic theory states that atoms can neither be created nor destroyed. Then how was the first even atom created in this blank space? Is it physically possible to create an atom?

Hello! (Wave) The following DFA is given: I want to find the language that it recognizes. The alphabet is $\Sigma=\{0,1\}$. Isn't the language this one: $(0^{\ast} 1^{+} 0^{\ast} )^{+}$? Also I want to draw a dfa that recognizes the following languages and that have the referred number of...

Hello, Could someone provide me with a good proof or explain me here how we can derive Slater determinant for N fermions by starting with the vacuum state and the creation operators with anticommutation equations. I see that the idea of both these structures is similar but I cannot work it out...

Question: Estimate the rate of continuous creation required to keep the density of the universe constant at 10-26kg/m3. Express your answer in protons/year/km3. Attempt: Assuming a spherical matter-dominated Friedmann universe, we know from solving the fluid equation that ρ ∝ 1/a3 (where ρ is...

Okay, please forgive what seems to be a religious debate cause I assure you it is not. I am merely seeking your opinion on an exchange. Now, I said that pair production is an "example of creation that requires no conscious act". To this example my opponent said the following: “Matter creation...

Homework Statement Need to show that [a,f(a,a^\dagger]=\frac{\partial f}{\partial a^\dagger} Homework Equations [a,a^\dagger]=1 The Attempt at a Solution Need to expand f(a,a^\dagger) in a formal power series. However I don´t know how to do it if the variables don´t commute.

Please consider this statement from Alan Guth (from his book "The Inflationary Universe"). The context is the creation of magnetic monopoles: The monopoles, therefore, are the surviving remnants of the chaos in the Higgs fields immediately after the phase transition. Guth then goes on to...

Homework Statement This problem is from Lahiri and Pal (2nd edition) Exercise 1.4: Suppose in a system there are operators which obey anticommutation relations ##[a_{r},a^{\dagger}_{s}]_{+}\equiv a_{r}a^{\dagger}_{s}+a^{\dagger}_{s}a_{r}=\delta_{rs}## and ##[a_{r},a_{s}]_{+}=0,## for...

Let's say a train powered by electric third rail drives around without friction on a circular track, and light is shining out of the train windows, said light carries angular momentum, like light emitted from rotating or revolving things tend to do. Where does that angular momentum come from...

It seems during cosmic inflation the universe expands at an accelerated rate. This expansion is driven by the potential of the inflaton field. There's a slow role off of the inflaton potential as the universe inflates very rapidly and then the potential drops off rather sharply and the energy of...

OK, I'm sure I'm just not thinking about this the right way, so please point out my simple mistake. Imagine a charged particle and 2 observers. Observer S is stationary relative to the charged particle, so sees no magnetic field from it. Observer A moves back and forth in front of the...

If I create an electromagnetic wave with electric and magnetic fields partially out of phase, would it behave the same as a mass with velocity less than the speed of light?

As I understand it VSl theories say that when the speed of light changes the law of conservation of energy is violated, so the origin of matter at the big bang is a consequence of this change in C. But do they not also say the the reported variations of the fine structure constant maybe a hint...

Homework Statement Consider two photons, one with energy ε1 = 2MeV traveling to the right, and the other with energy ε2 = 3MeV moving tot he left. The two photons collide head-on and produce a positron-electron pair. Suppose the the electron and positron move along the same axis as the photons...

Hi everyone, I am currently preparing myself for my Bachelor thesis in local quantum field theory. I was encouraged by my advisor to read the books of M. Reed and Simon because of my lag of functional analysis experience but I have quite often problems understand the “obvious” conclusions. For...

Lets suppose we have a photon and it will going to create a particle particle mass is ##16.10^-29## kg.I used ##E=mc^2## to find the solution and I found 90 MeV but the answer is 180 where did I made wrong. Thanks

Say I have a hamiltonian with fermion creation / annihilation operators like this: \sum_{k_1,k_2,k_3,k_4} c_{k_1,\uparrow}^{\dagger} c_{k_2,\downarrow}^{\dagger} c_{k_3,\downarrow} c_{k_4,\uparrow} where the k's are momenta and the arrows indicate spin up / spin down. Can I commute operators...

From a purely theoretical standpoint, I'm quite comfortable with the concept of particle creation/annihilation, but, as a chemist, I cannot but feel that there's something missing in the way of interpretation, so I came up with the following 'explanation' of the phenomenon based on the measured...

Galilean creation is one of a number of proposed alternatives to inflationary cosmology. This paper; http://arxiv.org/abs/1504.05710, Galilean Creation of the Inflationary Universe, takes the idea a step further by showing how it can transit smoothly to the single field inflationary model...

- a|n>=C|n-1> - a+|n>=D|n+1> And because |n-1> is normalized, <n-1|n-1>=1: (<n|a+)(a|n>)=C2 Thus, <n|a+a|n>=C2 Where a is the annihilation operator and a+ is the creation operator I don't understand this as...

Hi Likely a stupid question. If atoms vibrate with heat, why don't hot objects make a sound, i.e transferring vibrations to the surround atoms (air) into our eardrums? They vibrate on ultra-infra sound? Or it's a extremely weak sound? or this is not the same vibration as the cause for sound? or...

So I understand there's rarely such a thing as an original idea. Perhaps this is already out there if so let me know. From what I understand, one interesting way to look at the speed of light, is that it is the speed that everything travels at except when it has mass to slow it down. It is the...

1. Can a proton be created in a particle accelerator that doesn't use protons? For instance, an "electron-positron" collider? I understand baryon number needs to be conserved, so this would necessitate the accompanying creation of an anti-proton, but I'm wondering if these colliders have...

My question is a little more broad than I could make clear in the title but here goes. First of all, to be clear, am I correct in understanding that light behaves in precisely the same way as an electron in the sense that there exists a wave function which evolves according the Schrodinger...

Anyone having an idea of how to solve problem 3a) file:///C:/Users/Administrator/Downloads/handin1%20(2).pdf ? I've been stuck for a great while but have not idea.

how can it be that mater can never be created nor destroyed. I just don't understand I was taught that both energy and mater can never be created nor destroyed yet they are interchangeable. to me this sounds like a direct contradiction of its self am I missing a major fundamental. Evenus1

People say that Multiverse doesn't exist, But as per #TheGrandDesign by Stephen Hawking, Quantum Fluctuations led to the creation of tiny universes out of nothing. A few of these reached a critical size, then expand in an inflationary manner, formed galaxies, stars and, in at least one case...

I've gotten a bit confused about the creation of the neutron star/pulsar, so I was hoping someone could point me in the right direction :) As fusion stops, when reaching the iron phase, the outer layers (hydrogen, helium, carbon... etc.) gets pulled in-wards do to gravity. This creates a bounce...

We have a large mass, and we increase it slowly- dropping in one atom at a time. Will a black hole form suddenly, or will it gradually become blacker with the addition if each atom? I assume that a mass marginally below the threshold must at least partially have the properties of a black hole...

Hello! I am reading about the creation and annihilation operators and I don't get how you find the creation operator from the annihilation one. The creation one is \hat{a}=\sqrt{\frac{m \omega}{2 \hbar}}\left( \hat{x}+\frac{i \hat{p}}{m \omega}\right) and the annihilation operator is...

I asked this in another thread and was told this question should have had its own thread so as to not hijack the other thread. That question was: Has anyone calculated how much if any gold is produced in the sun? which is likely almost none do to the differences between fusion and fission and...

1. If anyone can help me solve this optimization problem it would be much appreciated! Imagine making a tent in the shape of a spherical cap (a sphere with a lower portion sliced away by a plane). Assume we want the volume to be 2.2m3. The floor of the tent is cheaper material than the rest...

I got a question in my mind as to how the tiny dot of matter during the big bang contained so much energy that could create the universe. Remember this tiny dot contained so much energy that it could transform this energy into matter in the form of the universe (Remember E=MC2). The Quantum...

One of the sources of matter creation is pair production when 2 gamma ray photons collide and produce electron positron pair. The other would be Quantum Fluctuations which create again electron-positron pairs. What are the other methods of matter creation other than the above two?