A new algorithm counts degrees of freedom in open EFTs from equations of motion using dual advanced equations for non-Lagrangian systems with constraints and gauges.
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Lopez Nacir, R
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abstract
We generalize the effective field theory of single clock inflation to include dissipative effects. Working in unitary gauge we couple a set of composite operators in the effective action which is constrained solely by invariance under time-dependent spatial diffeomorphisms. We restrict ourselves to situations where the degrees of freedom responsible for dissipation do no contribute to the density perturbations at late time. The dynamics of the perturbations is then modified by the appearance of `friction' and noise terms, and assuming certain locality properties for the Green's functions of these composite operators, we show that there is a regime characterized by a large friction term \gamma >> H in which the \zeta-correlators are dominated by the noise and the power spectrum can be significantly enhanced. We also compute the three point function <\zeta\zeta\zeta> for a wide class of models and discuss under which circumstances large friction leads to an increased level of non-Gaussianities. In particular, under our assumptions, we show that strong dissipation together with the required non-linear realization of the symmetries implies |f_NL| ~ \gamma/(c_s^2H) >> 1. As a paradigmatic example we work out a variation of the `trapped inflation' scenario with local response functions and perform the matching with our effective theory. A detection of the generic type of signatures that result from incorporating dissipative effects during inflation, as we describe here, would teach us about the dynamics of the early universe and also extend the parameter space of inflationary models.
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Constructs a manifestly diagonal-BRST-invariant Schwinger-Keldysh path integral for open non-Abelian gauge theories with arbitrary physical initial states, yielding Ward-Takahashi-Slavnov-Taylor identities and a Keldysh BRST symmetry for the Open EFT.
Develops open EFT for stochastic inflation with a distinct stochastic RG channel, derives nonlocal master equations including Fokker-Planck and Klein-Kramers forms, and demonstrates stochastic renormalization with an analytic regulator.
Derives gauge-invariant influence functionals for photons and Stueckelberg fields in open U(1) gauge EFTs via BRST on the in-in contour after integrating out matter.
The equilateral bispectrum from massive scalar exchange in inflation is not universally negative in the full EFT of inflation; its sign depends on a critical ratio of operator coefficients.
Classical and quantum correlation functions of inflationary perturbations diverge exponentially with e-folds when interactions are relevant, even if forced to agree at an intermediate time.
A pedagogical review of Love numbers and tidal responses for black holes and compact objects in general relativity and extensions.
citing papers explorer
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Counting Degrees of Freedom in Open Effective Theories
A new algorithm counts degrees of freedom in open EFTs from equations of motion using dual advanced equations for non-Lagrangian systems with constraints and gauges.
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Schwinger-Keldysh Path Integral for Gauge theories
Constructs a manifestly diagonal-BRST-invariant Schwinger-Keldysh path integral for open non-Abelian gauge theories with arbitrary physical initial states, yielding Ward-Takahashi-Slavnov-Taylor identities and a Keldysh BRST symmetry for the Open EFT.
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Stochastic inflation as an open quantum system II: open effective field theory and stochastic matching
Develops open EFT for stochastic inflation with a distinct stochastic RG channel, derives nonlocal master equations including Fokker-Planck and Klein-Kramers forms, and demonstrates stochastic renormalization with an analytic regulator.
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Gauging Open EFTs from the top down
Derives gauge-invariant influence functionals for photons and Stueckelberg fields in open U(1) gauge EFTs via BRST on the in-in contour after integrating out matter.
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Massive Exchange and the Sign of the Equilateral Bispectrum
The equilateral bispectrum from massive scalar exchange in inflation is not universally negative in the full EFT of inflation; its sign depends on a critical ratio of operator coefficients.
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Classical and quantum evolution of inflationary fluctuations
Classical and quantum correlation functions of inflationary perturbations diverge exponentially with e-folds when interactions are relevant, even if forced to agree at an intermediate time.
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Love numbers of black holes and compact objects
A pedagogical review of Love numbers and tidal responses for black holes and compact objects in general relativity and extensions.