Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: General Theory of Spontaneous Emission Near Exceptional Points   We present a general theory of spontaneous emission at exceptional points
(EPs)---exotic degeneracies in non-Hermitian systems. Our theory extends beyond
spontaneous emission to any light--matter interaction described by the local
density of states (e.g., absorption, thermal emission, and nonlinear frequency
conversion). Whereas traditional spontaneous-emission theories imply infinite
enhancement factors at EPs, we derive finite bounds on the enhancement, proving
maximum enhancement of 4 in passive systems with second-order EPs and
significantly larger enhancements (exceeding $400\times$) in gain-aided and
higher-order EP systems. In contrast to non-degenerate resonances, EPs are
associated with non-Lorentzian emission curves, leading to enhancements that
scale polynomially with the resonance quality factor.

22
The categories of this paper are: chao-dyn
16
The categories of this paper are: stat
36
The categories of this paper are: cmp-lg
37
The categories of this paper are: supr-con
25
The categories of this paper are: patt-sol
20
The categories of this paper are: acc-phys
14
The categories of this paper are: math-ph
33
The categories of this paper are: plasm-ph
2
The categories of this paper are: math
15
The categories of this paper are: nucl-ex
31
The categories of this paper are: ao-sci
30
The categories of this paper are: q-alg
1
The categories of this paper are: cs
19
The categories of this paper are: eess
11
The categories of this paper are: hep-lat
5
The categories of this paper are: gr-qc