Title: Stability of Dirac Liquids with Strong Coulomb Interaction Show Chinese title

Title: 狄拉克流体在强库仑相互作用下的稳定性

Abstract: We develop and apply the Diagrammatic Monte Carlo technique to address the problem of stability of the Dirac liquid state (in a graphene type system) against strong long-range part of the Coulomb interaction. So far, all attempts to deal with this problem in the field-theoretical framework were limited either to perturbative or RPA treatments, with diametrically opposite conclusions. Our calculations aim at the approximations-free solution with controlled accuracy by computing vertex corrections from higher-order skeleton diagrams and establishing the renormalization group flow of the effective Coulomb coupling constant. We unambiguously show that with increasing the system size $L$ (up to $ln(L) \sim 40$), the coupling constant always flows towards zero; i.e. the two dimensional Dirac liquid is an asymptotically free $T=0$ state with divergent Fermi velocity. Show Chinese abstract

Abstract: 我们开发并应用了图解蒙特卡洛技术，以解决狄拉克液态（在石墨烯类系统中）对抗库仑相互作用的强长程部分的稳定性问题。 到目前为止，所有在场论框架下处理这个问题的尝试都局限于微扰或RPA处理，得出的结论截然相反。 我们的计算旨在通过从高阶骨架图中计算顶点修正，并建立有效库仑耦合常数的重整化群流，从而获得无近似、精度可控的解决方案。 我们明确地表明，随着系统尺寸$L$增大（达到$ln(L) \sim 40$），耦合常数始终流向零；即二维狄拉克液态是一个渐近自由的$T=0$状态，其费米速度发散。