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This article investigates the properties of a scalar fifth force that arises in a scalar tensor-theory with a chameleon screening mechanism in the context of gravity space missions like the MICROSCOPE experiment. In such an experiment, the propagation of the chameleon field inside the nested cylinders of the experiment causes a fifth force when the cylinders are not perfectly coaxial. We propose a semianalytic method to compute the field distribution and the induced fifth force and compare it to a full numerical simulation, in settings where the cylindrical symmetry is broken. The scaling of the fifth force with both the parameters of the model and the geometry of the experiment is discussed. We show that the fifth force is repulsive, hence adds a destabilizing stiffness that should be included in the force budget acting on the detector. This opens the way to a new method to constrain a scalar fifth force in screened models. [ABSTRACT FROM AUTHOR]

For any quantum algorithm given by a path in the space of unitary operators we define the computational complexity as the typical computational time associated with the path. This time is defined using a quantum time estimator associated with the path. This quantum time estimator is fully characterized by the Lyapunov generator of the path and the corresponding quantum Fisher information. The computational metric associated with this definition of computational complexity leads to a natural characterization of cost factors on the Lie algebra generators. Operator complexity growth in time is analyzed from this perspective leading to a simple characterization of the Lyapunov exponent in the case of chaotic Hamiltonians. The connection between complexity and entropy is expressed using the relation between quantum Fisher information about quantum time estimation and von Neumann entropy. This relation suggests a natural bound on computational complexity that generalizes the standard time energy quantum uncertainty. The connection between Lyapunov and modular Hamiltonian is briefly discussed. In the case of theories with holographic duals and for those reduced density matrix defined by tracing over a bounded region of the bulk, quantum estimation theory is crucial to estimate quantum mechanically the geometry of the tracing region. It is suggested that the corresponding quantum Fisher information associated with this estimation problem is at the root of the holographic bulk geometry. [ABSTRACT FROM AUTHOR]

We investigate the renormalization group flows of multicomponent scalar theories with U (1) gauge symmetry using the functional renormalization group method. The scalar sector is built up from traces of matrix fields that belong to simple, compact Lie algebras. We find that in these theories the local potential approximation (LPA) is not a one-loop closed truncation in general, even at zero gauge coupling. If, however, we add a U (1) factor to the Lie algebra structure, then the LPA always becomes one-loop closed. In accordance with our earlier findings, fluctuations introduce anomalous, regulator dependent gauge contributions, which are only consistent with the flow equation for a given set of gauge fixing parameters. We establish connections between regularization procedures in the standard covariant and the R ξ gauges arguing that one is not tied by introducing regulators at the level of the functional integral, and it is allowed to switch between schemes at different levels of the calculations. We calculate β functions, classify fixed points, and clarify compatibility of the flow equation and the Ward-Takahashi identity between the scalar wave function renormalization and the charge rescaling factor. [ABSTRACT FROM AUTHOR]