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Allison F. Pinto

Publications and source records attributed to Allison F. Pinto.

3 recordsLinked to original sources

Homological Quantum Mechanics

We provide a formulation of quantum mechanics based on the cohomology of the Batalin-Vilkovisky (BV) algebra. Focusing on quantum-mechanical systems without gauge symmetry we introduce a homotopy retract from the chain complex of the harmonic oscillator to finite-dimensional phase space. This induces a homotopy transfer from the BV algebra to the algebra of functions on phase space. Quantum expectation values for a given operator or functional are computed by the function whose pullback gives a functional in the same cohomology class. This statement is proved in perturbation theory by relating the perturbation lemma to Wick's theorem. We test this method by computing two-point functions for the harmonic oscillator for position eigenstates and coherent states. Finally, we derive the Unruh effect, illustrating that these methods are applicable to quantum field theory.

hep-th

Cosmological Perturbations in Double Field Theory

We explore perturbative double field theory about time-dependent (cosmological) backgrounds to cubic order. To this order the theory is consistent in a weakly constrained sense, so that for a toroidal geometry it encodes both momentum and genuine winding modes. We give a self-contained discussion of the consistency problems and their resolution, including the role of cocycle factors and the $O(d,d,\mathbb{Z})$ duality. Finally, as a first step toward the computation of cosmological correlation functions, we propose a generalized scalar-vector-tensor decomposition and use it to construct gauge invariant generalized Bardeen variables. Compared to standard cosmology there are fewer tensor modes but more vector and scalar modes.

hep-th

Gauge Invariant Perturbation Theory via Homotopy Transfer

We show that the perturbative expansion of general gauge theories can be expressed in terms of gauge invariant variables to all orders in perturbations. In this we generalize techniques developed in gauge invariant cosmological perturbation theory, using Bardeen variables, by interpreting the passing over to gauge invariant fields as a homotopy transfer of the strongly homotopy Lie algebras encoding the gauge theory. This is illustrated for Yang-Mills theory, gravity on flat and cosmological backgrounds and for the massless sector of closed string theory. The perturbation lemma yields an algorithmic procedure to determine the higher corrections of the gauge invariant variables and the action in terms of these.

hep-th