State Definition and 1000 Threads

Hi .. I have this problem needed to solve I hope can find someone help me.. 1- Is the system of three cubic in pure state <ψABC| each pair cubic in bell state |φ+>? 2- Consider a system of two cubits in state Is the measurement without selecting observable which changes the state of a cubit...

Consider a system with a time-dependent Hamiltonian. We know that the evolution of the state of this system, is given by ## \displaystyle |\Psi(t_1)\rangle=T \exp\left( -i \int_{t_0}^{t_1} dt H(t) \right) |\Psi(t_0)\rangle ##. Do you think you can prove that the path integral formula for the...

Long time ago I encountered a claim that if you fix some energy interval [E_A,E_B], the measure of the set \{(x,p)\;|\;E_A\leq H(x,p)\leq E_B\} where H(x,p) is some classical Hamiltonian, is going to be approximately proportional to the number of energy eigenstates contained in the energy...

i have found one article state something like this:"""Any real evolution (macroevolution) requires an expansion of the gene pool, the addition of new genes (genons) with new information for new traits as life is supposed to move from simple beginnings to ever more varied and complex forms...

Hello Forum, My understanding is that the state of the system is ##|\Psi>##. We can take the inner product between the state ##|\Psi>## and the eigenstates of the position operator ##\hat{x}##: $$<x|\Psi>=\Psi(x)$$ The function ##\Psi(x)## is the wave function we are initially introduced to in...

1. For arbitrary real numbers a & b, exactly one of the three relations hold: a < b, a > b, a = b. How do I state this more formally while also being correct?2. The attempt at a solution a, b ∈ ℝ ( (a < b) ⊕ ( a > b ) ⊕ ( a = b) ) From this I made a truth table 2^3 entries long, and what we...

Is it in a Quantum superposition, and then only in a mixed state when finding the reduced state of a qubit from an entanglement of multiple qubits?

Hello! I am going to enroll in a Solid State physics course and I want to know what good books are out there on the subject at an undergrad level. Any suggestions are appreciated! Thanks!

Ecosystems are open systems, they receive solar energy and other materials from outside the ecosystem and migration of animals is also witnessed. I read Physics uptil class XII and have done a bit of research on google books and have come across these three books: 1.Towards a Thermodynamic...

Let K be any Matrix, not necessarily the hamitonian. Is $$e^{-Kt}\left|\psi\right>$$ equal to $$e^{-K\left|\psi\right>t}$$ even if it is not the the eigenvector of K? I think so as i just taylor expand the $$e^{-Kt}$$ out but I want to confirm. In that case can i say that...

Using Optical Computing, what is the max amount of state changes that 1 transistor could theoretically have within 1 second? I once read that an electrical transistor could achieve 100 billion state changes per second, but I'm wondering what the number is for light, *and what it could...

If you have a density matrix \rho, there is a basis |\psi_j\rangle such that \rho is diagonal in that basis. What are the conditions on \rho such that the basis that diagonalizes it is unique? It's easy enough to work out the answer in the simplest case, of a two-dimensional basis: Then \rho...

Hi all, I was reading Arnold Neumaier's excellent article on the Vacuum Fluctuation Myth, and ran upon one part I have a question about: he notes that "in bare quantum field theory with a cutoff, the vacuum is a complicated multiparticle state depending on the cutoff – though in a way that it...

Homework Statement I have ##C= NK_B (\frac{\epsilon}{K_B T})^{2}e^{\frac{\epsilon}{K_B T}}\frac{1}{(e^{\frac{\epsilon}{K_BT}}+1)^2} ## and need to sketch ##C## vs. ##T## Homework Equations See above The Attempt at a Solution I have ##C= NK_B (\frac{\epsilon}{K_B...

When beryllium donates a pair of electrons to oxygen, that's oxidation, and the metal is Be(II). When carbon and oxygen share 6 electrons, 2 from carbon and 4 from oxygen, this is also oxidation. Of carbon. Even though it got more electrons, and even, I heard, has a negative charge. When...

Hello Forum, The state of a quantum system is indicated by##\Psi## in Dirac notation. Every observable (position, momentum, energy, angular momentum, spin, etc.) corresponds to a linear operator that acts on ##\Psi##.Every operator has its own set of eigenstates which form an orthonormal basis...

Hi My question is not long, but it is very broad; Is nanotechnology simpy just a rebranding of material science? Is there anything else to it? I have not really seen it used outside chemistry and material science. Do simple nanomachinery exist? I guess on a more speculative level it exists...

Some materials, notably graphene and some other 2D nanomaterials, possesses spin-polarized edge states, e.g., where one edge may allow the conduction of spins oriented "up" while the opposite edge only allows conduction of "down" spins. My question is not why these spin-polarized states exist...

I'm trying to calculate a Wigner Function of an entangled state, and I'm not quite sure how to proceed. I have created this state by sending in vacuum and a squeezed state into a 50/50 BS, where the output state has a density operator: $$\rho_{34}=S_{3}S_{4}S_{34}|00\rangle_{34}\langle...

Homework Statement Using Hund's rules, find the ground state L, S and J of the following atoms: (a) fluorine, (b) magnesium, and (c) titanium. Homework Equations J = L + S The Attempt at a Solution I'm having trouble understanding what L, S and J mean on a basic level. I read the textbook...

From the path integral approach, we know that ## \displaystyle \langle x,t|x_i,0\rangle \propto \int_{\xi(0)=x_i}^{\xi(t_f)=x} D\xi(t) \ e^{iS[\xi]}##. Now, using ## |x,t\rangle=e^{-iHt}|x,0\rangle ##, ## |y\rangle\equiv |y,0\rangle ## and ## \sum_b |\phi_b\rangle\langle \phi_b|=1 ## where ## \{...

Hello, Im having some issues with my task. 1. Homework Statement The heat generation rate of a cylindrical fuel (D=0.2 m and 1 m long) is 160 kW. The thermal conductivity of the fuel is 100 W/mK and its surface temperature is maintained at 283 K. Determine the temperature at the axis...

Homework Statement I'm currently working on a homework set for my intermediate QM class and for some reason I keep drawing a blank as to what to do on the first problem. I'm given three potentials, V(x), the first is of the form {A+Bexp(-Cx^2)}, the others I'll leave out. I'm asked to draw the...

A popular video I just watched described Fred Hoyle's discovery that the elements of the universe are created in stars. Key to his theorizing was the prediction that fusion would produce of a new state of carbon that had never been observed and which theory predicted would be unstable. Hoyle...

Hi, initially I would like to express that if you look at the first question it asks the rate at which the production goes from up to down, and ıf there is a rate I think the result should include time unit, but when I look at the solution result only consists of numbers ( the multiplication of...

Homework Statement Which cannot be the structure of two acoustic branches, nor three acoustic branches? Simple cubic, FCC, BCC, diamond cubic, NaCl lattice Homework Equations N/A http://solid.fizica.unibuc.ro/cursuri/solid_en/curs_solid_EN.pdf#page=61...

Hi guys! I study Electrical Engineering and, don't-know-why, I don't know anything about state space. Now I'm working on a project where I have a non-linear system. The first task in the project is to separate the linear and the non-linear part of this system, and then obtain the state space...

Hey guys, According to most pop science sources, "before" the Universe started to exist, there were no time, which can be understand easily as time is only possible if there are at least two existing object (e.g. two quarks, two atoms, etc.). Time as I understand it is a measurement of...

Homework Statement A particle of mass ##m## is in a spherically symmetric potential ##V = -\alpha\delta(|r|-a)##. Find the minimum value of ##\alpha## such that there is at least one bound state. Homework Equations ##u = \frac{R}{r}## ##-\frac{\hbar^2}{2m} \frac{d^2u}{dr^2} + \left[V +...

Homework Statement An interaction occurs so that an instantaneous force acts on a particle imparting a momentum ## p_{0} = \hbar k_{0}## to the ground state SHO wave function. Find the probability that the system is still in its ground state. Homework Equations ##\psi _{0} =\left(...

Homework Statement Given ##\psi = AR_{21}[BY_1^1 + BY_1^{-1} + CY_1^0]##, find ##\left<L_z\right>## and ##\left<L^2\right>##. (This is not the beginning of the homework problem, but I know my work is correct up to here. I am not looking for a solution, only an answer as to whether or not my...

The question asks: A physical device can be in three states: A,B,C. The device operates as follows (all time units are in hours): The device spends an exponentially distributed amount of time in stateAA (with mean of 12minutes) and then with probability 0.6 goes to state B, and with...

Hi all, I am reading a book about fundamental quantum mechanics, in which there mentioned many time about the product state ##|a\rangle|b\rangle## of two states ##|a\rangle## and ##|b\rangle## . To my understanding, product state means to combine two small systems to get a bigger one. So I am...

Hey guys, I need some help. Here's my task: Here's what I came up with: I need to calculate prob(x1|z1), prob(x1|z2) and so on and then just write down which has the highest probability. To do that, I would use Bayes rule, but for that, I need p(z1|x1) and p(z1). How do I get these? I have...

I saw another post about this but i didn't quite find what i was looking for there so i thought i'd give it a go instead with a thread. Homework Statement Calculate the exact value of the kinetic energy of the hydrogen atom in its ground state. No more information is given, we are referred to...

Here is the Problem Here is the construction, Hoping that I have done it correct "State with reasons that $\angle$ ACB is bisected by line OC" Many THanks (Party)

What exactly determines a ships ability to withstand extremely high sea states?

As much as I have understood, virtual particles keep appearing and disappearing in a vacuum state. This leads to zero-point energy, Casimir effect etc. Now, I want to know if there is a lifetime (i.e. a time limit) for which these virtual particles can exist before disappearing. Also can there...

Hi, I am a student from the Netherlands in 6V, the year before university, and I'm doing research on Quantum Computing. However, I have difficulty understanding the four states of two entangled qubits, $$\left|00\right> \\ \left|01\right> + \left|10\right> \\ \left|01\right> - \left|10\right>...

Hello! I am a bit confused about the relation between the singlet configuration and symmetry of the system. So in the spin case, for 2, 1/2 particles, the singlet configuration is antisymmetric. But I read that the quarks are always in a singlet configuration, which means that they are symmetric...

Hi, I am a student in the Netherlands, and I'll be attending university next year. However, I am doing some form of research on Quantum Computing with another student for our so-called "profielwerkstuk" but my understanding of Quantum Physics and math is sometimes not at the level that is...

Hi, I was curious to know what the perception of quantum chaos is. It seems a bit on the fringe, but at the same time it seems interesting. An adviser I'm considering working for works on both solid state physics applications and does some theoretical work in quantum chaos, so I'm wondering if...

Suppose there is a test chamber containing liquid nitrogen. The container is insulated and only a small opening is there so that chamber is exposed to atmospheric condition. As the saturation temperature of liquid nitrogen is -196 degree Celsius at 1 atm pressure. chamber will remain at -196...

Hi, As is commonly known, u = u(T,v) h = u(T,p) I've worked with some maths proofs of this a while ago, but do you guys have an intuitive way of understanding this without the maths, that is, why the state function for internal energy is defined by intensive volume and enthalpy with pressure...

I thought this could be explained as follows: a singlet state is one with ##S=0##. Electrons have spin ##\frac{1}{2}## or ##\frac{-1}{2}##, and in the ##1s^2## state there are two electrons. For it to be a triplet state both electrons would have to be spin ##\frac{1}{2}## which isn't allowed, by...

What really are Pointer States in Zurek stuff? is it an eigenstate or mixed states Zurek seems to be saying that you can reprepare Pointer States even if they are macroscopic. What can you say?

Homework Statement In a coherent state ##|\alpha\rangle##, letting ##P(n)## denote the probability of finding ##n^{\text{th}}## harmomic oscillator state. Show that $$\displaystyle{\langle\hat{n}\rangle \equiv \sum\limits_{n}n\ P(n)=|\alpha|^{2}}$$ Homework Equations The Attempt at a...

Indiana officials are trying to block almost 45,000 black citizens from voting Seems the voter's rights group wants the Justice department to look into this and the local police want to leave it with the local county prosecutors they work with. Either way, Police spokesman Bursten said the...

Homework Statement Estimate the ground state energy (eV) for an exciton in Si. εSi = 12 ε = 1.0359×10−10 Effective masses me* = 0.26me mh* = 0.36me effective mass = 0.15me Values of h 6.626×10−34 J⋅s 4.136×10−15 eV⋅s Values of ħ Units 1.055×10−34 J⋅s 6.582×10−16 eV⋅s Homework Equations E1 =...

Good day, I try to differentiate GHZ-state and W-state using three tangle. Suppose The value three tangle for GHZ-state equal to 1 while W-state equal to 0. I used three tangle formula, $$\tau_{ABC}=\tau_{A(BC)}-\tau_{AB}-\tau_{AC}=2(\lambda^{AB}.\lambda^{AB}+\lambda^{AC}.\lambda^{AC})$$...