Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Universality in fast quantum quenches   We expand on the investigation of the universal scaling properties in the
early time behaviour of fast but smooth quantum quenches in a general
$d$-dimensional conformal field theory deformed by a relevant operator of
dimension $\Delta$ with a time-dependent coupling. The quench consists of
changing the coupling from an initial constant value $\lambda_1$ by an amount
of the order of $\delta \lambda$ to some other final value $\lambda_2$, over a
time scale $\delta t$. In the fast quench limit where $\delta t$ is smaller
than all other length scales in the problem, $ \delta t \ll
\lambda_1^{1/(\Delta-d)}, \lambda_2^{1/(\Delta-d)}, \delta
\lambda^{1/(\Delta-d)}$, the energy (density) injected into the system scales
as $\delta{\cal E} \sim (\delta \lambda)^2 (\delta t)^{d-2\Delta}$. Similarly,
the change in the expectation value of the quenched operator at times earlier
than the endpoint of the quench scales as $<{\cal O}_\Delta> \sim \delta
\lambda (\delta t)^{d-2\Delta}$, with further logarithmic enhancements in
certain cases. While these results were first found in holographic studies, we
recently demonstrated that precisely the same scaling appears in fast mass
quenches of free scalar and free fermionic field theories. As we describe in
detail, the universal scaling refers to renormalized quantities, in which the
UV divergent pieces are consistently renormalized away by subtracting
counterterms derived with an adiabatic expansion. We argue that this scaling
law is a property of the conformal field theory at the UV fixed point, valid
for arbitrary relevant deformations and insensitive to the details of the
quench protocol. Our results highlight the difference between smooth fast
quenches and instantaneous quenches where the Hamiltonian abruptly changes at
some time.

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The categories of this paper are: math
32
The categories of this paper are: atom-ph
5
The categories of this paper are: gr-qc
27
The categories of this paper are: comp-gas
30
The categories of this paper are: q-alg
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The categories of this paper are: nlin
25
The categories of this paper are: patt-sol
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The categories of this paper are: adap-org
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The categories of this paper are: quant-ph
31
The categories of this paper are: ao-sci
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The categories of this paper are: stat
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The categories of this paper are: astro-ph
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The categories of this paper are: alg-geom
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The categories of this paper are: hep-ph
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The categories of this paper are: eess
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The categories of this paper are: hep-lat