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Rob Tan's user avatar
Rob Tan's user avatar
Rob Tan's user avatar
Rob Tan
  • Member for 4 years
  • Last seen this week
5 votes
2 answers
2k views

Euler-Lagrange equation in curved spacetime

4 votes
0 answers
91 views

What happens when the same action extremal value can be obtained in more than one path in the configuration space?

4 votes
2 answers
316 views

A discussion about $\text{SO}(1,3)$ transformation generators on states and four-momentum little group

3 votes
1 answer
316 views

How there can be an explicit coordinate dependence on the Lagrangian, if this arises from a Lagrangian density?

3 votes
2 answers
187 views

Can electromagnetic field be another manifestation of the spacetime?

3 votes
1 answer
112 views

Interaction hamiltonian of Unruh-De Witt detector in Schrödinger picture

2 votes
1 answer
130 views

Choice of scalars in Einstein-Hilbert action

2 votes
1 answer
618 views

Demonstration Wick's theorem

2 votes
2 answers
1k views

Pauli matrices, Levi-Civita symbol and Einstein notation

2 votes
2 answers
588 views

About $\phi^4$ theory

1 vote
2 answers
378 views

Some questions about Normal Ordering in QFT

1 vote
1 answer
255 views

Sign of four-dimensional translation operator

1 vote
2 answers
206 views

Field variations at boundary - Glass of water problem

1 vote
0 answers
36 views

On the history of field theories on curved spacetime [closed]

1 vote
0 answers
137 views

Deriving Euler-Lagrange equation for vector field in curved spacetime

1 vote
2 answers
191 views

Meaning of Bogolyubov transformations

1 vote
1 answer
129 views

Scale factor in conjugate scalar field inside conformally flat spacetime

1 vote
0 answers
45 views

Annihilation of two-particles intermediate states

1 vote
0 answers
162 views

Derivation of Kruskal to Schwarzchild coordinate transformation

1 vote
1 answer
64 views

Schwinger action principle derivation in Parker-Toms

1 vote
1 answer
800 views

Ricci scalar variation on conformal transformation and scalar field lagrangian

1 vote
1 answer
344 views

Different definitions of Riemann tensor components

0 votes
0 answers
28 views

Spacetime dimension by variational principle

0 votes
0 answers
49 views

Are time and normal ordering idempotent (meta-)operators?

0 votes
0 answers
89 views

Dimension of covariant and contravariant vectors on a manifold

0 votes
2 answers
259 views

What happened to the phase of creation and annihilation operators?

0 votes
2 answers
142 views

Confusion about word "vector" in "basis vectors" of General Relativity

0 votes
1 answer
86 views

What is $\langle 0|p\rangle$?

0 votes
1 answer
83 views

Time derivative in vacuum-to-vacuum transition amplitude for the real scalar field

0 votes
0 answers
58 views

Components of tridimensional vector in flat four dimensional space