Is absolute zero possible in a complete vacuum?
38151
Why is absolute zero considered to be asymptotical? Wouldn't regions such as massive gaps between galaxy clusters have temperatures of absolute zero?
38720
Is it possible to speak about changes in a physical constant which is not dimensionless?
82894
Why cannot fermions have non-zero vacuum expectation value?
48899
Is it possible to create matter?
22988
Are vacuum fluctuations really happening all the time?
50289
The vacuum light speed: Is it really constant, i.e., independent of location in space-time?
97369
Does the limit of $e^{-1/z^4}$ as $z\to 0$ exist?
152865
If a superconductor has zero resistance, does it have infinite amperage?
64373
Would a pendulum swing indefinitely in a frictionless vacuum?
140005
How will a particle with energy less than $V_{\rm min}$ behave?
155558
If energy is only defined up to a constant, can we really claim that ground state energy has an absolute value?
74101
How is a vacuum able to propagate light?
42334
Does $\lambda$ $\mathbf u$ $= 0$ imply $\lambda = 0$ or $\mathbf u$ $= 0$?
5247
Physical meaning of non-trivial solutions of vacuum Einstein's field equations
101152
Can vacuum fluctuations change the position of an electron?
80060
Is $\frac{1}{\infty}$  equal zero?
113249
Does time exist in a vacuum?