88 research outputs found
Gauge Is More Than Mathematical Redundancy
Physical systems may couple to other systems through variables that are not gauge invariant. When we split a gauge system into two subsystems, the gauge-invariant variables of the two subsystems have less information than the gauge-invariant variables of the original system; the missing information regards degrees of freedom that express relations between the subsystems. All this shows that gauge invariance is a formalization of the relational nature of physical degrees of freedom. The recent developments on boundary variables and boundary charges are clarified by this observation
On single and double soft behaviors in NLSM
In this paper, we study the single and double soft behaviors of tree level
off-shell currents and on-shell amplitudes in nonlinear sigma model(NLSM). We
first propose and prove the leading soft behavior of the tree level currents
with a single soft particle. In the on-shell limit, this single soft emission
becomes the Adler's zero. Then we establish the leading and sub-leading soft
behaviors of tree level currents with two adjacent soft particles. With a
careful analysis of the on-shell limit, we obtain the double soft behaviors of
on-shell amplitudes where the two soft particles are adjacent to each other. By
applying Kleiss-Kuijf (KK) relation, we further obtain the leading and
sub-leading behaviors of amplitudes with two nonadjacent soft particles.Comment: 41 pages, 6 tables, 9 figures, minor revised, more content about
nonadjacent double soft limit, update the reference
Double-soft limits of gluons and gravitons
Open Access, (c) The Authors. Article funded by SCOAP 3
Limits of JT gravity
We construct various limits of JT gravity, including Newton-Cartan and
Carrollian versions of dilaton gravity in two dimensions as well as a theory on
the three-dimensional light cone. In the BF formulation our boundary conditions
relate boundary connection with boundary scalar, yielding as boundary action
the particle action on a group manifold or some Hamiltonian reduction thereof.
After recovering in our formulation the Schwarzian for JT, we show that
AdS-Carroll gravity yields a twisted warped boundary action. We comment on
numerous applications and generalizations.Comment: 41 pages, 3 figures, 1 table; v2: Matches published version +
Footnote 11; v3: Corrected typo in Carrollian/Galilean generalized dilaton
potentia
Null to time-like infinity Green’s functions for asymptotic symmetries in Minkowski spacetime
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