Questions tagged [quantum-entanglement]
Quantum entanglement is the mechanism by which quantum correlations between two sub-systems survive even after being physically separated from an interaction region. The correlations could in principle survive without neither time nor space constraint.
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Does Bell’s theorem rule out changing hidden variables?
In the EPR experiment, it is said that there are predictions that are made if there are hidden variables determined by something locally in each particle that results in a correlation in entanglement. ...
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How do physicists talk about spin of individual particles when the universe is massively entangled?
The following two things seem to be true:
(1) The universe is massively entangled because the wave function that describes the entire universe has measure 1 of being entangled. Further, given how ...
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What is the percentage of entangled content (matter and radiation) in the universe after big bang? And what are the implications?
I searched for entangled matter in cosmological context but didn't find anything that actually answers my question.
Big bang nucleosynthesis is actually a series of chain reactions that produces a ...
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Computing Fubini-Study expectation values over $\mathbb{C}P^n$
In finite-dimensional textbook quantum mechanics, we postulate that states of our system are rays in a Hilbert space $\mathcal{H}$ with dimension $\dim{\mathcal{H}} = n+1$ where $n \in \mathbb{N}$, ...
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Partial trace on a two-mode continuous-variable quantum state
I have the following continuous-variable entangled state
$$ \left|\psi\right\rangle_{1,2}= \int_{-\infty}^{+\infty} dq_{1} dq_{2}~\psi(q_{1}) f_{G}(q_{2})e^{\frac{i}{2} q_{1}q_{2}}\left|q_{1}\right\...
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Does the no signalling theorem in quantum mechanics beg the question?
I had always thought similarly and then came across a paper here that argues this.
The abstract is as follows:
Many authors state that quantum nonlocality could not involve any controllable ...
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Is quantum entanglement the only example in physics where consistent correlations happen without a cause? [duplicate]
So as far as I am aware, there is currently no cause that explains how exactly two entangled particles remain correlated even when separated at a large distance. If there is a cause, it is presumed to ...
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How do you determine if an Hamiltonian allows entanglement and when?
Sorry for the vague setup, but I'm a noob and I'm trying to understand, so please be patient. Let's say that I have a tight-binding, 2D, square lattice Hamiltonian
$$
H = H_t + H_{interaction} + H_{\...
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Measuring Incompatible observables simultaneously of an entangled electron [duplicate]
Given that a pair of electrons are in the state $$\psi =\frac{ {|00}\rangle \pm {|11}\rangle }{\sqrt{2}}$$ (in the the spin-$x$ eigenbasis) . If we measure the spin along $x$ axis of one of the ...
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What are the implications of the EPR bridge information metric being invariant under all conditions, including distance in this universe?
What if the reason why instantaneous state information is able be transmitted between entangled particles through an EPR bridge is that the metric that this is conveyed in is invariant under all ...
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Decoherence model of two qubits interacting with correlated multimode fields - open quantum system
I read paper on open quantum system, that talk about non-Markovian process and memory effects.
they described the system as a generic decoherence model of two qubits interacting with correlated ...
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What does doubly-entangled $W$-like state do with three-particle setup?
First, is entanglement of three particles in $W$-like state deliberately possible (and not by chance)? Second, is the following statement correct?
In the doubly entangled $W$ state, represented as
$$ |...
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Does it make sense to talk about individual energies of interacting quantum particles?
Does it make any sense to talk about energy of any one particle in an interacting system? For example if we talk about a system of two coupled quantum harmonic oscillators of same mass and frequency, ...
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Mermin's EPR paradox explanation [closed]
I am reading N. D. Mermin, Bringing home the atomic world: Quantum mysteries for anybody
. The main part of the article is pretty clear to me. But I am not sure how quantum mechanics described in ...
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Does local realism imply entangled photons are equal (or opposite)?
I'm watching a video about Bell's inequality and how there can be no local hidden variables. They explain it using photons and whether they pass through a polarizer or not when they're oriented at ...
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