The tag has no wiki summary.

learn more… | top users | synonyms

0
votes
0answers
22 views

Local EPR-experiments with photons in vacuum?

When two entangled particles are measured in an EPR experiment, we consider these events as non-local. Generally I agree. But does this also apply to a pair of photons in vacuum? (and if so, why?) ...
0
votes
3answers
59 views

“Spooky action at a distance” or particle correlation at the time of their creation?

In Bell test experiments, two particles that are a singlet are measured and are found to be correlated. The correlation leads us to believe that they are somehow connected non-locally: the ...
3
votes
1answer
131 views

Non-Locality of Space - QFT (Srednicki's book)

I was going through Mark Srednicki's book on QFT. It says in the relativistic limit the Schrodinger equation becomes something like : $$ i\hbar\frac{\partial}{\partial t} \psi(\vec x,t) = ...
2
votes
2answers
160 views

Why does the Dopfer EPR experiment require coincidence counting?

Dopfer Momentum-EPR experiment (1998) seems to provide a interesting tweak in the EPR experiment. To read more details on this experiment, see: ...
2
votes
0answers
48 views

Pseudo-randomness of observables

There is a somewhat recent paper by Colbeck and Renner that, given the assumptions — 1) QM accurately predicts the correct statistical results in experiment (which so far has always been found to be ...
1
vote
0answers
54 views

Nonlocal games: The CSCH game

The problem that I am having is that I don't see how they come up with the probabilities mentioned on Slide #7 here: https://www.ipam.ucla.edu/publications/opws1/opws1_9367.pdf first I don't ...
0
votes
1answer
102 views

Non-locality and Bell's theory

Non-Locality – (just ) one more question? I have read comments that Bell’s theory proves quantum mechanics is non-local, and also comments that it does not. I have read a comment by a very eminent ...
1
vote
1answer
137 views

Dimension & non - locality problem in string theory

I have some questions with string theory: Why is it that there is exactly 4 large spacetime dimensions while the rest remain small? It is a nonlocal QFT. How could that fit in GR?
4
votes
2answers
172 views

Non-local Lagrangian contact interaction

Conside a contact interaction given by a delta function on their worldlines. Use a gauge fixed Lagrangian for two point particles in terms of their proper times $t$ and $t^{\prime}$. Is it possible to ...
2
votes
2answers
69 views

Is it possible to determine the state or values of something without measuring it

To give context to this question, I am currently looking into non-locality / hidden variables / Bell's Theorem, EPR / etc. I've noticed the assertion that the values / state of something when ...
8
votes
1answer
240 views

Is this field redefinition for free scalar field theory non-local?

The action of free scalar field theory is as follows: $$ S=\int d^4 x \frac{\dot{\phi}^2}{2}-\frac{\phi(m^2-\nabla^2)\phi}{2}. $$ I have been thinking to redefine field as ...
4
votes
1answer
493 views

Is spacetime an illusion?

In consistent histories, for gauge theories, can the projection operators used in the chains be not gauge invariant? In quantum gravity, for a projection operator to be gauge invariant means it has ...
11
votes
1answer
123 views

CHSH violation and entanglement of quantum states

How is the violation of the usual CHSH inequality by a quantum state related to the entanglement of that quantum state? Say we know that exist Hermitian and unitary operators $A_{0}$, $A_{1}$, ...
8
votes
1answer
37 views

Sub and super multiplicativity of norms for understanding non-locality

In relation to various problems in understanding entanglement and non-locality, I have come across the following mathematical problem. It is most concise by far to state in its most mathematical form ...
20
votes
2answers
84 views

Bell polytopes with nontrivial symmetries

Take $N$ parties, each of which receives an input $s_i \in {1, \dots, m_i}$ and produces an output $r_i \in {1, \dots, v_i}$, possibly in a nondeterministic manner. We are interested in joint ...
15
votes
4answers
70 views

Why can't noncontextual ontological theories have stronger correlations than commutative theories?

EDIT: I found both answers to my question to be unsatisfactory. But I think this is because the question itself is unsatisfactory, so I reworded it in order to allow a good answer. One take on ...
5
votes
1answer
194 views

If strings are infinitely extended, are they nonlocal?

To completely localize a string within any bounded region of space, no matter how large, requires an infinite energy. Does this mean strings modes are inherently nonlocal?