All Questions
Tagged with quantum-foundations or foundations
308 questions
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Are fields and particles physically different entities? [closed]
Can a field in space-time be equivalently thought of as a sea of particles?
In fluid mechanics we usually switch to a field-like picture because of the large number of particles involved and the ...
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What makes Hardy's Paradox different from the Quantum Bomb Tester?
It seems both rely on the idea of interaction-free measurements; is the difference in the nature of what they are "measuring"? I understand that they are made to demonstrate different things,...
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Quantization conditions and uniqueness
In modern physics, classical theories are intuitively understood as approximations of an underlying quantum theory of some kind, I have essentially two questions about this:
Can every classical ...
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326
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What happen with wavefunction immediately after a measurement?
One of the postulates of quantum mechanics, introduced by Dirac, says that immediately after a measurement of an observable $\hat A$ the wavefunction abruptly becomes an eigenfunction of $\hat A$. In ...
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Is analog data truly continuous, or ultimately discrete due to physical limitations?
I've been thinking about the physical nature of analog vs digital data. Analog data is often described as “continuous,” while digital data is “discrete.” However, I'm struggling to understand how true ...
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Physical Significance of Relative Quantities [closed]
One of the tenets of relativity lies in the fact that the form of any physical equation must not depend on a particular choice of a coordinate system
I was wondering if this implies the fact that some ...
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165
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On deriving classical to modern physics using minimal axioms [closed]
I am not a physicist but was curious on the differentiation between classical and modern physics.
I keep hearing the physics before $1905$ was classical and usually classical physics is associated to ...
- 147
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What are the conceptual foundations of Lagrangian formulation? [duplicate]
When learning Lagrangian mechanics in a standard mechanics course, it is typically introduced as an alternative formulation of classical mechanics which can be derived from Newtonian mechanics. ...
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Is Quantum Mechanics Self-Consistent?
Quantum mechanics postulates the following (and please correct me if I'm wrong):
Every physical state of a system is uniquely identified with a ray in a Hilbert space $|\Psi\rangle \in \mathcal{H}$ ...
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-6
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324
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The concept of speed in relativity [closed]
A point which is sometimes raised by people in the foundations of physics, is how to make sense of the concept of "velocity" in relativity, given that neither space nor time are coordinate-...
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Causality in the context of Quantum Information
It is very well known that in the context of quantum information, the simplest entanglement-generating circuit is the following one:
The state of the two Qbits right before the final measurement will ...
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How to intuitively understand the relation between an quantum mechanical operator and it's corresponding infinitesimal dynamic operator?
In quantum mechanics, we know that the generator of the infinitesimal time translation operator $$U(dt) = e^{-\frac{i}{\hbar}\hat{H}dt}$$ is the Hamiltonian $\hat{H}$.
Similarly, the generator of the ...
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Validity of EPR Argument and Causality
From my understanding, Bell's theorem rests on the EPR argument, where it is argued that either the quantum state does not completely specify a physical system, or the theory is non-local.
Because ...
- 914
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191
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Am I right or wrong about Wheeler's mental retrocausality problem involving one remote star and gravitational lensing?
Tell me where I am wrong.
One of Wheeler’s supposed examples of retrocausality speaks of a remote star, a black hole or other gravitation lens in between it and earth, and astronomers on earth who can ...
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Has anyone constructed an explicit hidden-variable theory that reproduces the predictions of quantum mechanics for two separated qubits?
Consider the Hilbert space
$$\mathcal{H} = \mathrm{span}\left( \{ |0\rangle\ |0\rangle, |0\rangle\ |1\rangle, |1\rangle\ |0\rangle, |1\rangle\ |1\rangle \} \right) \cong \mathbb{C}^4$$
of (pure) ...
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