Search Results
| Search type | Search syntax |
|---|---|
| Tags | [tag] |
| Exact | "words here" |
| Author |
user:1234 user:me (yours) |
| Score |
score:3 (3+) score:0 (none) |
| Answers |
answers:3 (3+) answers:0 (none) isaccepted:yes hasaccepted:no inquestion:1234 |
| Views | views:250 |
| Code | code:"if (foo != bar)" |
| Sections |
title:apples body:"apples oranges" |
| URL | url:"*.example.com" |
| Saves | in:saves |
| Status |
closed:yes duplicate:no migrated:no wiki:no |
| Types |
is:question is:answer |
| Exclude |
-[tag] -apples |
| For more details on advanced search visit our help page | |
Results tagged with quantum-mechanics
Search options not deleted
user 23389
Quantum mechanics describes the microscopic properties of nature in a regime where classical mechanics no longer applies. It explains phenomena such as the wave-particle duality, quantization of energy, and the uncertainty principle and is generally used in single-body systems. Use the quantum-field-theory tag for the theory of many-body quantum-mechanical systems.
0
votes
How does quantum world affect us and why should I care about it?
The laws of quantum mechanics are always valid, but in everyday circumstances those laws can be well-approximated by those of classical mechanics.
Your question seems to be, "why should I care about …
- 15.3k
1
vote
Is the uncertainty principle axiomatic or derived?
Although the Uncertainty Principle can be derived from other aspects of quantum mechanics, it is still regarded as a principle, rather than as a result or a relation, because it is an empirical princi …
- 15.3k
3
votes
Accepted
Symmetric, antisymmetric and mixed symmetry particles
You may indeed have heard that an electron is antisymmetric, whereas a photon is symmetric. What does this mean?
Suppose I have a system of several electrons. They could be orbiting a nucleus, for ex …
- 15.3k
7
votes
How $\pi$ is derived from quantum mechanics
The value of $\pi$ cannot be derived from QM. The article discusses the observation that $\pi$ (in fact the Wallis product for $\pi$) appears in a derivation of the energy levels of hydrogen. I don't …
- 15.3k
2
votes
What is the energy of a superposition of energy eigenstates?
If energy is conserved, how so that a measurement of the energy of a state, such as
$$
\psi = N (\phi_1 + \phi_2),
$$
could result in two different energies? I think your question is easiest to tackle …
- 15.3k
2
votes
Is Interpretation of state vectors and density matrices according to Frequentist or Bayesian...
Heisenberg discusses probability in his Physics and Philosophy. He first stresses that quantum mechanics contains objective, frequentist probabilities:
Probability in mathematics or in statistical …
- 15.3k
14
votes
Factor 2 in Heisenberg Uncertainty Principle: Which formula is correct?
The strongest limit without loss of generality is
$$
\Delta p\Delta x \ge \frac12 \hbar,
$$
this is always true. Whilst $\Delta p\Delta x \ge \hbar$ might often be true, it is not always true.
The $ …
- 15.3k
1
vote
Unitarity of PMNS matrix
I will offer two reasons. First, unitarity of mixing matrices insures that probabilities sum to one. The probability of an oscillating neutrino having electron, muon or tau flavour should equal one.
…
- 15.3k
2
votes
Probability and the many-worlds interpretation
Your observation is correct. If tossing a coin were a quantum measurement, in the many-worlds interpretation of quantum mechanics (MW), there would be a branch of "worlds" in which the outcome was alw …
- 15.3k
5
votes
Accepted
Are Forces Involved Non-Local?
We must be careful with what we mean by "locality." There are two relevant related, but distinct, concepts:
Einsteinian non-locality: superluminal communication/transfer of information is possible. …
- 15.3k
1
vote
Accepted
Are physical constants determined by their observation?
Let us divide a calculation in physics into two pieces: the dynamics, which describes how a state changes with time, and the initial conditions, which describes the state at a particular time.
In q …
- 15.3k
1
vote
Accepted
Understanding notation regarding particles states and wavefunctions
If we know there is a particle(s) in state $i_1$ why do we need
$r_1$? Does the state $i_1$ not specify position?
The fact that the particle is in a state $|\psi\rangle$ does not specify the pa …
- 15.3k
5
votes
Which theory explains the path of a photon in Young's double-slit experiment?
Your question touches upon the characteristic features and controversies of quantum mechanics. You want to know whether any theory can predict or explain which slit a photon passed through in a double …
- 15.3k
2
votes
Is a dice roll deterministic?
You are asking about the origin of probability in dice rolls. As argued convincingly by e.g. Jaynes in LoS, probability in dice rolls and coin tosses originates from our ignorance of the initial condi …
- 15.3k
1
vote
2
answers
982
views
Unitarity in QFT and measuring unitarity
I am trying to make sense of statements about unitarity in this popular science article about Nima and Jaroslav's new idea.
My first query is that it is claimed that unitarity is a pillar of quantum …
- 15.3k