ABSTRACT
Quantum annealing is a way to solve a combinational optimization problem where quantum fluctuation is induced by transverse fields. Recently, a bifurcation-based quantum annealing with spin-1 particles was suggested as another mechanism to implement the quantum annealing. In the bifurcation-based quantum annealing, each spin is initially prepared in [Formula: see text], let this state evolve by a time-dependent Hamiltonian in an adiabatic way, and we find a state spanned by [Formula: see text] at the end of the evolution. Here, we propose a scheme to generate multipartite entanglement, namely GHZ states, between spin-1 particles by using the bifurcation-based quantum annealing. We gradually decrease the detuning of the spin-1 particles while we adiabatically change the amplitude of the external driving fields. Due to the dipole-dipole interactions between the spin-1 particles, we can prepare the GHZ state after performing this protocol. We discuss possible implementations of our scheme by using nitrogen vacancy centers in diamond.
ABSTRACT
The transverse-field Ising model is one of the fundamental models in quantum many-body systems, yet a full understanding of its dynamics remains elusive in higher than one dimension. Here, we show for the first time the breakdown of ergodicity in d-dimensional Ising models with a weak transverse field in a prethermal regime. We demonstrate that novel Hilbert-space fragmentation occurs in the effective nonintegrable model with d≥2 as a consequence of only one emergent global conservation law of the domain wall number. Our results indicate nontrivial initial-state dependence for nonequilibrium dynamics of the Ising models with a weak transverse field.
ABSTRACT
We report a case of adult sacrococcygeal teratoma resected by an abdominosacral approach. A cystic mass 13 cm in diameter in the pelvic cavity and left hydronephrosis were detected incidentally by abdominal computed tomographic (CT) scan in a 55-year-old man. The pelvic tumor extending from the presacral area to the coccyx was resected via a combined abdominal and transsacral approach. The resected specimen weighed 700 g and the pathological diagnosis was mature teratoma. While the sacrococcygeal area is the most frequent site of teratoma in infants, it is a rare site in adults. This is to our knowledge, the 30th case report of adult sacrococcygeal teratoma in Japan. At one month after the operation the patient had no bowel dysfunction and no dysbasia, but he had mild bladder dysfunction requiring self-catheterization twice a day at twelve months. The patient had no evidence of disease at twenty months after the operation.