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1d
awarded  Civic Duty
2d
comment Why does humidity cause a feeling of hotness?
OK, he is saying tempratures between 30°C and 36°C at high humidity are worse than temperatures greater than 37°C at low humidity. Not sure why it wasn't clear to me at first.
Jul
27
comment Why does humidity cause a feeling of hotness?
Is there a typo in the last sentence?
Jul
15
comment Mass density of dark matter in solar system near us
Or in other words, roughly 400 thousand protons' mass of dark matter per cubic meter or about half a proton's mass per cubic centemeter.
Jul
15
comment Mass density of dark matter in solar system near us
With error bars (adding uncertainties in quadrature) it is $(0.4\pm 0.1)$GeV/cm$^3$.
Jul
11
comment Transition from one state to another in Quantum Mechanics
Nice answer, but I would leave out "Single particle theories don't really work for reasons discussed in lots of books on quantum field theory. A very clear discussion is given in "Quantum Field Theory for the Gifted Amateur" by Lancaster and Blundell Chapter 8." Also I think the "Me" in your evolution operator equation should just be "e".
Jul
6
comment Is the Legendre transformation a unique choice in analytical mechanics?
I wonder if there is a typo in the following sentence: "... does not happen for field theories and interacting particles theories (it does happen for the point particle, though)". Its seems a bit unclear as obviously point particles can also be interacting.
Jun
29
answered Single field vs single clock inflation?
Jun
29
answered Possible values of an observable are the eigenvalues of an operator
Jun
18
awarded  Yearling
Jun
7
comment How many particles in $\phi_0(x)^2|0\rangle$?
One more question: shouldn't $$N{\phi^+}^2(x)|0\rangle = 2 {\phi^+}^2(x)|0\rangle$$ be $$N{\phi^-}^2(x)|0\rangle = 2 {\phi^-}^2(x)|0\rangle$$ ?
Jun
7
accepted How many particles in $\phi_0(x)^2|0\rangle$?
Jun
7
comment How many particles in $\phi_0(x)^2|0\rangle$?
Thanks again for your help.
Jun
7
comment How many particles in $\phi_0(x)^2|0\rangle$?
Thanks, that's very helpful. Should the + and - be swapped around in that last line?
Jun
7
asked How many particles in $\phi_0(x)^2|0\rangle$?
Jun
6
accepted Order of index in Lorentz transform
Jun
6
comment Order of index in Lorentz transform
@bechira I think it would be interesting to know as its otherwise such a good qft textbook. I think the answer is by $\Lambda^\mu_\nu$ he means $\Lambda^\mu{}_\nu$.
Jun
6
revised Order of index in Lorentz transform
more detail added
Jun
6
asked Order of index in Lorentz transform
May
30
comment Cosmological Constant on the LHS of Einstein's Field Equation
@Conifold I disagree with your ether analogy. The ether is disfavored observationally and theoretically compared to relativity. While in the CC case there is no strong experimental or physical argument that favors the term being on the LHS or RHS of the equation.