Delay Update in Determinant Quantum Monte Carlo

Determinant quantum Monte Carlo (DQMC) is a widely used unbiased numerical method for simulating strongly correlated electron systems. However, the update process in DQMC is often a bottleneck for its efficiency. To address this issue, we propose a generalized delay update scheme that can handle both onsite and extended interactions. Our delay update scheme can be implemented in both zero-temperature and finite-temperature versions of DQMC. We apply the delay update scheme to various strongly correlated electron models and evaluate its efficiency under different conditions. Our results demonstrate that the proposed delay update scheme significantly improves the efficiency of DQMC simulations, enable it to simulate larger system size.Comment: 10 pages, 7 figure

The Follow-up Report of MRI After Transforaminal Endoscopic Surgery of Lumbar Disc Herniation with Spinal Stenosis

Objective: To observe the imaging changes of MRI in the responsible disc area after modifed TESSYS foraminal scopy in pa-tients with lumbar disc herniation (LDH), and to explore the postoperative repair time of the responsible disc area, so as to provide imaging reference for the rehabilitation plan of the patients. Materials: To investigate the VAS score and MRI imaging of patients with lumbar disc herniation and spinal stenosis after transforaminal endoscopic surgery, which to lay the foundation for the rehabilitation plan. Methods: Ten patients with lumbar disc herniation (L4/5, L5/S1) with spinal stenosis were collected and followed up by MRI and the VAS score on 1 week, 1 month, 4 months and 6 months after transforaminal endoscopic surgery. Results: The VAS score were signifcantly lower than those before operation (P 0.05) on 1 month and 6 months after operation. The high signal could be seen around the intervertebral foramen and nerve roots on the operation site on 1 week, 1 month and 4 months after operation Which disappeared at 6 months after operation. Con-clusion: The symptoms of low back and leg pain in patients with lumbar disc herniation and spinal canal stenosis disappeared after 1 month, while the infammatory reaction symptoms of intervertebral foramen and nerve root were disappeared on 6 months

Itinerant quantum critical point with frustration and non-Fermi-liquid

Employing the self-learning quantum Monte Carlo algorithm, we investigate the frustrated transverse-field triangle-lattice Ising model coupled to a Fermi surface. Without fermions, the spin degrees of freedom undergoes a second-order quantum phase transition between paramagnetic and clock-ordered phases. This quantum critical point (QCP) has an emergent U(1) symmetry and thus belongs to the (2+1)D XY universality class. In the presence of fermions, spin fluctuations introduce effective interactions among fermions and distort the bare Fermi surface towards an interacting one with hot spots and Fermi pockets. Near the QCP, non-Fermi-liquid behavior are observed at the hot spots, and the QCP is rendered into a different universality with Hertz-Millis type exponents. The detailed properties of this QCP and possibly related experimental systems are also discussed.Comment: 9 pages, 8 figure