Creation Definition and 310 Threads

I had a question today as a part of my studies which was 1) If space is ever expanding what is the pressure on the creating space (universe) upon creation and 2) at what rate might you assume the quantum field is also being created and is it being affected by this pressure of creation. This is...

Phares as pragmatically as I can, thus leaving aside observational issues such as light speed, Universe expansion, moving apart galaxies and the Universe having no edge. Focusing on the fact that an observer on Earth looking deep into space can effectivly see the oldest stars formed during the...

TL;DR Summary: the cosmology of Poe's "Eureka" vs "Genesis from the Spirit" of J.Slowacki Polish poet Juliusz Słowacki [1809-1849] wrote a mystical prose poem (or a prayer) entitled "Genesis from the Spirit". If we omit the mystical parts in the poem and leave only the purely material...

Hi. As far as I know, entanglement can initially only be created locally, for example by creating two photons at one place in a crystal, or by local forces. Sure, there's entanglement swapping, but the initial entanglement was still created locally. But I only know examples. Is there a general...

I read somewhere that when, say, an electron and positron annihilate, they create two photons which travel in opposite directions in order to conserve linear momentum. Is this true? What about pair production. Do you likewise need two photons to do this? Or, can you do it with one photon...

We are all familiar with ladder operators, such as QM harmonic oscillators or in QFT to produce energy states which are interpreted as particles. But when a creation operator raises the energy level of a system, where does that energy come from?

Every sites is writing the same, so I think it's not an error. Source-: https://dirtysalt.github.io/html/gfs.html https://www.cnblogs.com/fxjwind/archive/2012/07/17/2595494.html https://riverferry.site/2021-01-26-The-Google-File-System/ The detailed explanations isn't available in much English...

This is less of a nuclear physics question and more of an EE one, but I think this is the right place for it. There is a startup called Zap Energy and their approach to fusion is to create a inertial confinement pinch with an electrical discharge. This is a bit similar to what the Sandia labs...

So, I have a hamiltonian for screening effect, written like: $$ H=\sum_{k}^{}\epsilon_{k}c_{k}^{\dagger}c_{k}+ \frac{1}{\Omega}\sum_{k,q}^{}V(q,t)c_{k+q}^{\dagger}c_{k} $$ And I have to find an equation for the time evolution of the expected value of the operator ##c_{k-Q}^{\dagger}c_{k}##. I...

Just joined the forum after youtubes algorithm suggested a story documenting the ‘Chicago Pile’. I ended up watching a bunch of other power plant videos becoming more confused with each one. I apologize up front as I know nothing about the field of nuclear physics and not even sure if I’ll even...

Having had a look at the following video of the dipole antenna and the creation of EM radiation, which I completely understand, I had a look at the link http://hyperphysics.phy-astr.gsu.edu/hbase/Astro/procyc.html#c1 and the hydrogen fusion process within a star. Looking at the process how do...

Are there any papers or articles that reference black holes being the creations of the big bang or being considered in creating universes in alternate dimensions? Thanks for the help.

Looking for good sources, something beyond typical popular science but readable for a layperson that details current thinking on how various elements get created and distributed over time (supernova, neutron star mergers etc) and implications for evolution of life. Any recommendations?

https://phys.org/news/2020-10-carbon-creation-astrophysics.html Back in 2016 - Recent results in nuclear astrophysics https://arxiv.org/abs/1605.07810 From the abstract -

Hello everyone, I'm new here and I'm struggling with the mathematical formalities in quantum mechanics. $$\langle n+1|b^\dagger bb^\dagger + \frac 12 |n \rangle = \langle n+1|b^\dagger bb^\dagger |n \rangle + \langle n+1| \frac 12 |n \rangle $$ $$ = \langle n+1|b^\dagger b \sqrt{n+1} |n+1...

This seems like it should be an easy and obvious thing to look up, but I had the hardest time finding it. Is there any graph which shows, as I increase the beam energy of a particle accelerator, what particles can be produced at each energy? Just looking for something ballpark here. Obviously...

How do we know it;s redshift for certain? because unlike with stars the CMB doesn't have spectral lines nor other "similar" objects to compare to as it is everywhere and the same. From what I understand first came the theory and model of the Big bang, then Hubble saw that distant galaxies are...

Hello, Apart from the graviton postulate, which would permit such a mechanism, my question is: would a similar mechanism be possible with a stationary wave? (the simplest scenario I can immagine is of two opposing waves). My background is in DSP and Acoustics so I might get things wrong (a...

Hi, so I'm currently reading the book "QFT for the gifted amateur", and doing the exercises. In exercise 14.2, which in itself is fine, the authors say that you can show using Noether's theorem that for a transverse polarized photon of momentum q, the z-component of the spin operator obeys the...

The Mathpix Snip tool is quite impressive. I recommend you check it out! It could save you a lot of effort in trying to write $\rm\LaTeX$ code.

Regarding human vision and the retina: Where are these channels produced? To put it simply, is it produced in the eye or in the brain. For example; does light enter the eye, hits the retina and it applies a series of filters to produce these 2 different channels (the parvo and magno) and it...

Summary: A supply of negentropy into a system is necessary to create states of higher order and complexity. Since the origin and evolution of life involves the creation of ever more complex molecular arrangements of atoms, life could not start without a sufficient supply of negentropy. So when...

I have written the equation, with an unknown constant $$a^\dagger \lvert n\rangle = C_{n+1}\lvert n+1 \rangle$$ I then take the adjoint to get $$\langle n \rvert a = \langle n+1 \rvert C_{n+1}^\text{*}$$ I then multiply them to get $$\langle n \rvert aa^\dagger \lvert n \rangle = \langle n+1...

I'm unclear on what exactly an annihilation or creation operator looks like in QFT. In QM these operators for the simple harmonic oscillator had an explicit form in terms of $$ \hat{a}^\dagger = \frac{1}{\sqrt{2}}\left(- \frac{\mathrm{d}}{\mathrm{d}q} + q \right),\;\;\;\hat{a} =...

I have this theory; gravitation is a result of the right composition and amount of elements, combined with the right temperature with a flux of course. This means there are many possibilities to create gravity, and anti-gravity if switched 180 degrees. Am I far out? what's your thoughts?

If the creation of our universe went alongside with creation of a second universe wherein each particle in our universe had a counterpart particle in it with opposite momentum, could those universes (our+second one) be created from zero energy?

Cohererent states are defined as eigenstates of the annihilation operator. Never the creation operator is referred to. Is this just a convention or is more behind? What is the essential difference between eigenstates of the annihilation- versus the creation operator? Thank you very much in...

Excuse me for bad wording in the title, but there is only so much you can do with the character limit. So, has there ever been a proposal for a mechanism through which negative energy density could be created? Or the only possibility considered so far was that it would have been created in the...

Given a large enough energy source (nuclear?)... can I build a rocket that creates its own reaction mass via electron-positron pair production, and then derive thrust by accelerating the charged particles out the back with a magnetic nozzle?

Homework Statement Consider the state $$\psi_\alpha = Ne^{\alpha \hat a^\dagger}\phi_0, $$ where ##\alpha## can be complex, and ##N = e^{-\frac{1}{2}|\alpha|^2}## normalizes ##\psi_\alpha##. Find ##\hat N \psi_\alpha##. Homework Equations $$\hat N = \hat a^\dagger \hat a$$ $$\hat a\phi_n =...

Hi, When one quantizes EM the resulting gauge boson, the photon, ends up being its own antiparticle. From what I read of gluons, they have anti particles. I can follow how anti particles come about quantizing a complex-valued field like that for electrons. For the spin 1/2 case non-interacting...

The Compton wavelength of a particle is given by $$\lambda=\frac{h}{mc}.$$ One can construct an expression for the energy density ##\rho## of a particle of mass ##m## given by $$\rho = \frac{mc^2}{\lambda^3}=\frac{m^4 c^5}{h^3}.$$ What is the physical significance of the mass scale ##m## in the...

Homework Statement After proving the relations ##[\hat{b}^{\dagger}_i,\hat{b}^{\dagger}_j]=0## and ##[\hat{b}_i,\hat{b}_j]=0##, I want to prove that ##[\hat{b}_j,\hat{b}^{\dagger}_k]=\delta_{jk}##, however I'm not sure where to begin. 2. The attempt at a solution I tried to apply the...

red marker part in my book is very confusing. It says you will not succeed to create index by that. Is it trying to say that if we have two tables and there is a FK relation in them , then I won't be able to create index in either table? Can you please help with an example exactly when I...

I was recently reading about annihilation and creation operators in particle physics using the model of an harmonic oscillator, and then quantizing it. This is fine. I can understand it. But how does this quantization of the energy of the harmonic oscillator manifest physically? Is it that only...

Hi, http://curious.astro.cornell.edu/about-us/101-the-universe/cosmology-and-the-big-bang/general-questions/570-where-did-the-matter-in-the-universe-come-from-intermediate The website given above says that the matter was created via pair production process (like electron anti-electron...

Hi, if i understood correctly from pop-science literature, there is theoretical possibility of formation of wormholes like in this picture: https://en.wikipedia.org/wiki/File:Wormhole-demo.png bud you need some exotic particles (i think it means negative energy?). Now what i really don't...

How large was the universe at its moment of creation? Do we have a real answer for this? If so, how was this found out?

Generally, a change in altitude within a gravitational field is said to increase or decrease PE. I posit that the change in PE never occurs UNTIL there is a change in KE. Thus, in the case of an object with a constant velocity UP, there is no gain in PE until the instant that the thrust no...

From another thread: I see this claim made fairly often, but it does not seem correct to me. According to the MWI, the dynamics of the wave function is always unitary (there is no collapse), and a unitary process cannot "create" or "destroy" anything. All it can do is entangle things. So, for...

Hello In a paper I am working we have a two metal connected to each other, Within the ballistic approximation we adopt the Landauer approach and generate a pure spin current by applying a spin bias that is modeled as difference of spin-dependent chemical potentials across the interface. Can...

<Moderator's note: Image added because otherwise the thread might once become unreadable.> I have reason to believe this could have applications in physics, but right now it's just a mathematical result I came across recently. Either way, I think it is very interesting and fun to look at. This...

I was reading this thread by stevendaryl https://www.physicsforums.com/threads/second-quantization-vs-many-particle-qm.835472/ I have two questions 1. which QFT picture are those, Schrodinger, path integral or Heisenberg. 2.In QM the creation/annihilation operators raise and lower energies...

I know that a high frequency light beam is more likely to generate a virtual electron-positron pair than a low frequency one. Can this probability depend on the reference frame? It seems there is a paradox. How do we explain it?

Hello, I have read that Michio Kaku has made antimatter and photographed it when he was only a high schooler. I have read that the used Sodium-22 to produce positrons. How does that happen? I could not find some good sources of answers... Thanks.

Is it correct to assume that all known particles may be created as virtual particles in the vacuum? If so, is there a higher probability of a particular particle being produced than say some other particle type. For example, is an electron more likely to be created as a virtual particle than a...

My question has multiple parts, does the following paper: https://arxiv.org/abs/1405.0298 Disprove the possibility of creation of another universe through quantum fluctuations if heat death occurs? If it does could another universe still be created through quantum tunneling? Can quantum...

Hello, I've noticed that some professors will jump between second quantized creation/annihilation operators and wavefunctions rather easily. For instance \Psi_k \propto c_k + ac_k^{\dagger} with "a" some constant (complex possibly). I'm fairly familiar with the second quantized notation, and...

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...