Linked Questions
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Is what statisticians call a "random variable" what physicists call an "observable" in QM? [duplicate]
I read at http://www.statlect.com/fundamentals-of-probability/random-variables that
A random variable is a variable whose value depends on the outcome of a probabilistic experiment. Its value is a ...
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Why are transition amplitudes more fundamental than probabilities in quantum mechanics? [duplicate]
I am reading Quantum Theory: Concepts and Methods by Asher Peres.
Terminology used in the book:
$P_{\mu m}$ are "transition probabilities". They are the squares of "transition ...
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Why can’t quantum randomness be understood as epistemic? [duplicate]
I often hear people say that quantum randomness is “true randomness”, but I don’t really understand it. Please bear with my question.
Before the development of quantum physics, randomness is ...
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Quantum probability [duplicate]
I would like to get an idea of what "quantum probability" means and how it differs from classical frequentist or Bayesian probability. Can anyone enlighten me in non-too-technical terms?
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Is quantum superposition is real or is it due to the fact that we measure everything in probabilities like tossing a coin? [duplicate]
I know not much about Quantum mechanics but I know some basics in Quantum mechanics.
when a tossed coin is in air we cannot say what state it is in currently until we catch it (or 'measure it' in ...
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Why is psi square a possibility? [duplicate]
Is psi square just an assumption? Or there is a physical reason why they defined like that? My procedure is:
It is intuitive for me to think possibility is proportional to energy distribution. ...
김건형
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Density matrix formalism
The density matrix $\hat{\rho}$ is often introduced in textbooks as a mathematical convenience that allows us to describe quantum systems in which there is some level of missing information.
$\hat{\...
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Why is a Hermitian operator a "quantum random variable"?
To me, as a stupid mathematician, a random variable is a measurable function from some probability space $(\Omega, \sigma, \mu)$ to $(\Bbb{R}, B(\Bbb{R}))$. This makes sense. You have outcomes, events,...
user79317
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Why are expectation values of an observable important in QM?
I've been reading that expectation values of an observable is all what we can get and are the key quantities of the theory, but performing the same experiment many times would generate a distribution ...
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How do we know a quantum state isn't just an unknown classical state?
When an observer causes the wave function of a particle to collapse, how can we know that the wave function was not collapsed already before the measurement?
Suppose we measure the z-component of the ...
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How are quantum systems different from dice?
I've had this question for a while:
Is a state space $\mathcal{H}$ for a quantum system just a sample space in a probability space?
The question arises because i can't really tell a difference between ...
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Why hermitian, after all? [duplicate]
This question is going to look a lot like a duplicate, but I've read dozens of related posts and they don't touch the subject. Here we go.
Why are observables represented by hermitian operators?
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Is there a mathematical basis for Born rule?
Wave function determines complex amplitudes to possible measurement outcomes. The Born Rule states that the probability of obtaining some measurement outcome is equal to the square of the ...
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QFT Hilbert spaces over other rings than the complex numbers $\mathbb{C}$
I would like some help evaluating a physics theory recently proposed by a physics professor at the College of Dupage.
I think the theory is utterly wrong, for very simple reasons. If an amateur ...
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Multiplication of probability in quantum mechanics
Consider a ket-space spanned by the eigenkets of an observable $A$ and let $B$ be an additional observable on the same ket-space. We can build a filter that only lets an eigenvalue $a$ of $A$ through ...
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