Nonperturbative dynamics of (2+1)d ϕ4-theory from Hamiltonian truncation
Nonperturbative dynamics of (2+1)d ϕ4-theory from Hamiltonian truncation
复制标题
哈密顿截断的 (2+1)d ψ4 理论的非微扰动力学
DOI：
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发表时间：
2020
影响因子：
5.4
通讯作者：
Matthew T. Walters
中科院分区：
文献类型：
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作者：
N. Anand;E. Katz;Zuhair U. Khandker;Matthew T. Walters
我们使用 Lightcone 保形截断 (LCT)（哈密顿截断的一种版本）来研究 2+1 维度 ψ4 理论的非微扰实时动力学。该理论存在需要调节的紫外线发散。我们回顾了在具有总能量截止的哈密顿框架中，重整化必然是依赖于状态的，并且紫外敏感性不能用标准局部算子反项来取消。为了克服这个问题，我们提出了一种为光锥量化中的 (2+1)d ψ4 理论构建适当的状态相关反项的方案。然后，我们使用 LCT 和这个反项处方来研究 ψ4 理论，重点关注 ℤ2 对称性保持相。具体来说，我们将光谱计算为耦合的函数，并证明在（依赖于方案的）临界耦合处质量间隙的闭合。我们还计算了通用强耦合和临界点附近的洛伦兹不变两点函数，我们证明了红外普适性和应力张量迹的消失。
We use Lightcone Conformal Truncation (LCT)—a version of Hamiltonian truncation — to study the nonperturbative, real-time dynamics of ϕ4-theory in 2+1 dimensions. This theory has UV divergences that need to be regulated. We review how, in a Hamiltonian framework with a total energy cutoff, renormalization is necessarily state-dependent, and UV sensitivity cannot be canceled with standard local operator counter-terms. To overcome this problem, we present a prescription for constructing the appropriate state-dependent counterterms for (2+1)d ϕ4-theory in lightcone quantization. We then use LCT with this counterterm prescription to study ϕ4-theory, focusing on the ℤ2 symmetry-preserving phase. Specifically, we compute the spectrum as a function of the coupling and demonstrate the closing of the mass gap at a (scheme-dependent) critical coupling. We also compute Lorentz-invariant two-point functions, both at generic strong coupling and near the critical point, where we demonstrate IR universality and the vanishing of the trace of the stress tensor.