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Variational quantum algorithms aim at harnessing the power of noisy intermediate-scale quantum computers, by using a classical optimizer to train a parameterized quantum circuit to solve tractable quantum problems. The variational quantum eigensolver is one of the aforementioned algorithms designed to determine the ground-state of many-body Hamiltonians. Here, we apply the variational quantum eigensolver to study the ground-state properties of $N$-component fermions. With such knowledge, we study the persistent current of interacting SU($N$) fermions, which is employed to reliably map out the different quantum phases of the system. Our approach lays out the basis for a current-based quantum simulator of many-body systems that can be implemented on noisy intermediate-scale quantum computers., Comment: 24 pages, 8 figures

We present Qibo, a new open-source software for fast evaluation of quantum circuits and adiabatic evolution which takes full advantage of hardware accelerators. The growing interest in quantum computing and the recent developments of quantum hardware devices motivates the development of new advanced computational tools focused on performance and usage simplicity. In this work we introduce a new quantum simulation framework that enables developers to delegate all complicated aspects of hardware or platform implementation to the library so they can focus on the problem and quantum algorithms at hand. This software is designed from scratch with simulation performance, code simplicity and user friendly interface as target goals. It takes advantage of hardware acceleration such as multi-threading CPU, single GPU and multi-GPU devices., Comment: 15 pages, 12 figures, 5 tables,code available at https://github.com/qiboteam/qibo, final version published in QST

We propose a quantum circuit that creates a pure state corresponding to the quantum superposition of all prime numbers less than 2^n, where n is the number of qubits of the register. This Prime state can be built using Grover's algorithm, whose oracle is a quantum implementation of the classical Miller-Rabin primality test. The Prime state is highly entangled, and its entanglement measures encode number theoretical functions such as the distribution of twin primes or the Chebyshev bias. This algorithm can be further combined with the quantum Fourier transform to yield an estimate of the prime counting function, more efficiently than any classical algorithm and with an error below the bound that allows for the verification of the Riemann hypothesis. We also propose a Twin Prime state to measure the number of twin primes and another state to test the Goldbach conjecture. Arithmetic properties of prime numbers are then, in principle, amenable to experimental verifications on quantum systems., Comment: 10 pages, 4 figures, one reference and additional comments concerning the Twin Prime state and the Goldbach conjecture added

La amenorrea es un criterio para el diagnostico de la anorexia nerviosa (AN) según el DSM-IV-TR. Sin embargo, al comparar grupos de pacientes que cumplen todos los criterios de este manual para la AN con grupos de mujeres que los presentan todos salvo la amenorrea, algunos estudios no han encontrado diferencias significativas en la psicopatología típicamente asociadas con la AN. El propósito de nuestro estudio ha sido comparar variables demográficas, antropométricas, psicológicas y psicopatológicas, en ambos grupos. No se observaron diferencias estadísticamente significativas entre ambos grupos en las variables evaluadas, pero el grupo con amenorrea tenía un índice de masa corporal significativamente más bajo. Nuestros datos apoyan la hipótesis de que la amenorrea podría no ser un criterio diagnóstico útil para la AN.

This manuscript explores the characteristics of individuals diagnosed with an eating disorder who dropped out of treatment, compared with those who completed it. The participants were 196 patients diagnosed with eating disorders (according to DSM-IV-TR criteria) who consecutively began treatment for the first time in an eating disorders unit. They were assessed at baseline with a set of questionnaires evaluating eating habits, temperament, and general psychopathology. During the follow-up period, patients who dropped out were re-assessed via a telephone interview. In the course of a 2-year follow-up, a total of 80 (40.8%) patients were labeled as dropouts, and 116 (59.2%) remaining subjects were considered completers. High TCI scores in the character dimensions of Disorderliness (NS4) (p

We construct a tensor network that delivers an unnormalized quantum state whose coefficients are the solutions to a given instance of 3SAT, an NP-complete problem. The tensor network contraction that corresponds to the norm of the state counts the number of solutions to the instance. It follows that exact contractions of this tensor network are in the \#P-complete computational complexity class, thus believed to be a hard task. Furthermore, we show that for a 3SAT instance with $n$ bits, it is enough to perform a polynomial number of contractions of the tensor network structure associated to the computation of local observables to obtain one of the explicit solutions to the problem, if any. Physical realization of a state described by a generic tensor network is equivalent to finding the satisfying assignment of a 3SAT instance and, consequently, this experimental task is expected to be hard.

La anorexia nerviosa, como trastorno de la conducta alimentaria, está asociada a una elevada preocupación por el peso, a ideas sobrevaloradas respecto a la delgadez, a una alteración de la imagen corporal y a un miedo excesivo a engordar. En este trabajo estudiamos las diferencias en la distorsión de la percepción corporal en pacientes con anorexia nerviosa de inicio temprano vs. tardío mediante el Cuestionario de la forma corporal (Body Shape Questionnaire) de Cooper, Taylor, Cooper y Fairburn (1987). La muestra clínica estaba compuesta por un total 176 pacientes diagnosticadas de anorexia nerviosa (47.1%) y anorexia nerviosa atípica (52.9%). En el 21.4% de la muestra los síntomas aparecieron antes de los 14 años. El grupo de anorexia nerviosa de inicio temprano presenta una mayor distorsión de su imagen corporal que el grupo de anorexia nerviosa de inicio tardío.

We develop a coordinate space renormalization of massless Quantum Electrodynamics using the powerful method of differential renormalization. Bare one-loop amplitudes are finite at non-coincident external points, but do not accept a Fourier transform into momentum space. The method provides a systematic procedure to obtain one-loop renormalized amplitudes with finite Fourier transforms in strictly four dimensions without the appearance of integrals or the use of a regulator. Higher loops are solved similarly by renormalizing from the inner singularities outwards to the global one. We compute all 1- and 2-loop 1PI diagrams, run renormalization group equations on them and check Ward identities. The method furthermore allows us to discern a particular pattern of renormalization under which certain amplitudes are seen not to contain higher-loop leading logarithms. We finally present the computation of the chiral triangle showing that differential renormalization emerges as a natural scheme to tackle $\gamma_5$ problems., Comment: 28 pages (figures not included)

A microscopic calculation of ground state entanglement for the XY and Heisenberg models shows the emergence of universal scaling behavior at quantum phase transitions. Entanglement is thus controlled by conformal symmetry. Away from the critical point, entanglement gets saturated by a mass scale. Results borrowed from conformal field theory imply irreversibility of entanglement loss along renormalization group trajectories. Entanglement does not saturate in higher dimensions which appears to limit the success of the density matrix renormalization group technique. A possible connection between majorization and renormalization group irreversibility emerges from our numerical analysis., 26 pages, 16 figures, added references, minor changes. Final version

We study the triviality problem of λ φ 4 theory in a time-dependent space-time within a variational Gaussian approach. A unique, precarious ( λ B ∼-1/lnΛ) phase makes sense. As a consequence, λ R is compelled to lie in the range &, where & depends on the curvature.