chsh (an abbreviation of "change shell") is a command on Unix-like operating systems that is used to change a login shell. Users can either supply the pathname of the shell that they wish to change to on the command line, or supply no arguments, in which case chsh allows the user to change the shell interactively.
I want to understand how an experiment is carried out to test violations of the CHSH inequalities. I have read Wikipedia and one popular book on quantum mechanics. The Wikipedia article is too short and incomprehensible to me; in addition, the description from Wikipedia and from the book is...
In some derivations of the CHSH inequality, https://en.m.wikipedia.org/wiki/CHSH_inequality, the following arises :
$$CHS=\int A(a,l1)B(b,l1)dl1-\int A(a,l2)B(b',l2)dl2+\int A(a',l3)B(b,l3)dl3+\int A(a',l4)B(b',l4)dl4\\
=\int A(a,l)B(b,l)dl1-A(a,l)B(b',l)+A(a',l)B(b,l)+A(a',l)B(b',l)dl$$
1)...
I've spent some time setting up my simulation of a photonic EPR experiment and came up with an exact joint probability distribution for the outcomes ##P_{xy}(\alpha,\beta)##.
To calculate the CHSH number we need the probability of a coincidence for each of the possible settings which becomes a...
Bell's Inequality, P(a,b)-P(a,d)+P(c,b)+P(c,d) is calculated as:
S = a*b - a*d + c*b + c*d <= 2.
It is valid for all values of a, b, c and d between -1 and +1
It is also valid for counts, a=a's counts/total counts of a,b,c &d.
b, c,and d are derived similarly. Negative counts are not allowed...
The Bell Inequality tests are only valid for positive numbers, which is reasonable because counts and probabilities cannot be negative. CHSH generates a negative number, which means CHSH experiments are invalid.
Bell's Inequality can be violated by having a negative value.
For example...
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...
An animation of the CHSH experiment to generate correlated photons is at: http://www.animatedphysics.com/games/photon_longdistance_chsh.htm
@georgir has a program to show the calculations using the formula for photon detection
return Math.random() < (Math.cos(r(p-a)*2)+1)/2;
yields the...
In the hidden variable model for CHSH, I computed the probabilities for the CHSH operators to have results -4,-2,0,2,4, then the average S.
Using a computer program, I could find the minimum of that function, obtaining S>2 :
#include<stdio.h>
#include<math.h>
double PI=4.0*atan(1.0)...
The experiment is described at p26 of http://arxiv.org/abs/quant-ph/0402001
In this experiment we see that we sum measurement results and not measure the sum.
Is then the quantum measurement operator not :
$$S=A\otimes B\otimes\mathbb{1_{64}}-\mathbb{1_{4}}\otimes A\otimes...
Hi All,
First, the context for this question can be found in Wilde's Quantum Shannon Theory text on the arXiv, specifically the section starting at the bottom of page 98, entitled "Entanglement in the CHSH Game". My particular question relates to Exercise 3.5.11 on page 100 of the same...
I tried another approach to the problem of covariance like in Bell's theorem :from the definition ##Cov(A,B)=\langle\Psi|A\otimes B|\Psi\rangle-\langle\Psi|A\otimes 1|\Psi\rangle\langle\Psi|1\otimes B|\Psi\rangle## (##A=diag(1,-1)=B##)
we can see that this 'average' is in fact a quadratic form...
Bell's 1971 derivation
The following is based on page 37 of Bell's Speakable and Unspeakable (Bell, 1971), the main change being to use the symbol ‘E’ instead of ‘P’ for the expected value of the quantum correlation. This avoids any implication that the quantum correlation is itself a...
http://en.wikipedia.org/wiki/CHSH_inequality#Bell.27s_1971_derivation
The last step of the CHSH inequality derivation is to apply the triangle inequality. I see there are relative polarization angles, but I don't see any sides have defined length to make up a triangle. Where is the triangle?
Hi all.
At first, I'm not a physicist, I'm a programmer, and English is not my native language, that's why something in my text might sound not quite right.
While researching various quantum entanglement experiments (just a hobby) I found one great article written by supposedly...
Hello everybody,
I've been trying to understand the CHSH proof as it is listed on Wikipedia:
http://en.wikipedia.org/wiki/CHSH_inequality
I got to this without any problem:
E(a, b) - E(a, b^\prime) = \int \underline {A}(a, \lambda)\underline {B}(b, \lambda)[1 \pm \underline {A}(a^\prime...
Obviously a violation of the CHSH inequality means that local realistic theories are untenable.
If we sent two entangled photons towards detectors (far enough away that for information to travel, you'd require it to go faster than light). One reaches a detector before the other, so...
OK, here is an interesting assertion I haven't seen before. Thought I would see what some of the folks here think. The paper is:
Quantum Preferred Frame: Does It Really Exist? by J. Rembielinski, K. A. Smolinski (2009)
Abstract: "The idea of the preferred frame as a remedy for...
Homework Statement
I need to get the CHSH inequality from Bell's inequality
Homework Equations
|C(a, b) - C(a, b')| + |C(a', b) - C(a', b')| <= 2
to
-2 <= C(a, b) - C(a, b') + C(a', b) + C(a', b') <= 2
The Attempt at a Solution
I know the CHSH allows for no correlation of...