RESUMEN
Conventional lattice formulations of θ vacua in the 1+1-dimensional O(3) nonlinear sigma model suffer from a sign problem. Here, we construct the first sign-problem-free regularization for arbitrary θ. Using efficient lattice Monte Carlo algorithms, we demonstrate how a Hamiltonian model of spin-1/2 degrees of freedom on a two-dimensional spatial lattice reproduces both the infrared sector for arbitrary θ, as well as the ultraviolet physics of asymptotic freedom. Furthermore, as a model of qubits on a two-dimensional square lattice with only nearest-neighbor interactions, it is naturally suited for studying the physics of θ vacua and asymptotic freedom on near-term quantum devices. Our construction generalizes to θ vacua in all CP(N-1) models, solving a long-standing sign problem.
RESUMEN
Background: The novel coronavirus and its effect on our society are unprecedented. Given the recent pandemic, numerous measures have been taken to protect our communities. We sought to understand our school community's knowledge and the measures that were taken by our school for our safety. Objective: Our objective was to describe the overall understanding and attitudes of 8-12th grade students from a single institution during the initial phase of the Wisconsin's Governor's stay-at-home order. Methods: A voluntary web-based survey was communicated to 8-12th grade students through their online school portal. Data were collected and analyzed using SurveyMonkey. Results: There was a 20.2% response rate. Answers regarding the coronavirus, spread, and response to the coronavirus pandemic showed a high level of understanding of the virus and the actions necessary to prevent its spread. Conclusion: Eight-twelfth grade students have a high level of understanding of the virus, its effects, and the safety measures implemented to protect society.
RESUMEN
We provide strong evidence that the asymptotically free (1+1)-dimensional nonlinear O(3) sigma model can be regularized using a quantum lattice Hamiltonian, referred to as the "Heisenberg comb," that acts on a Hilbert space with only two qubits per spatial lattice site. The Heisenberg comb consists of a spin-half antiferromagnetic Heisenberg chain coupled antiferromagnetically to a second local spin-half particle at every lattice site. Using a world-line Monte Carlo method, we show that the model reproduces the universal step-scaling function of the traditional model up to correlation lengths of 200000 in lattice units and argue how the continuum limit could emerge. We provide a quantum circuit description of the time evolution of the model and argue that near-term quantum computers may suffice to demonstrate asymptotic freedom.
