The issue of gauge choice in the Landau problem and the physics of canonical and mechanical orbital angular momenta

doi:10.1016/j.aop.2018.03.019

	The issue of gauge choice in the Landau problem and the physics of canonical and mechanical orbital angular momenta
	Wakamatsu, M.1,2; Kitadono, Y.1; Zhang, P-M 1
刊名	ANNALS OF PHYSICS
	2018-05
卷号	392 页码:287-322
关键词	Landau problem Gauge choice Gauge-invariant formulation Path dependence Orbital angular momenta Nucleon spin decomposition
ISSN号	0003-4916
DOI	10.1016/j.aop.2018.03.019
英文摘要	One intriguing issue in the nucleon spin decomposition problem is the existence of two types of decompositions, which are representably characterized by two different orbital angular momenta (OAMs) of quarks. The one is the mechanical OAM, while the other is the so-called gauge-invariant canonical (g.i.c.) OAM, the concept of which was introduced by Chen et al. An especially delicate quantity is the g.i.c. OAM, which must be distinguished from the ordinary (gauge-variant) canonical OAM. We find that, owing to its analytically solvable nature, the famous Landau problem offers an ideal tool to understand the difference and the physical meaning of the above three OAMs, i.e. the standard canonical OAM, g.i.c. OAM, and the mechanical OAM. We analyze these three OAMs in two different formulations of the Landau problem, first in the standard (gauge-fixed) formulation and second in the gauge-invariant (but path-dependent) formulation of DeWitt. Especially interesting is the latter formalism. It is shown that the choice of path has an intimate connection with the choice of gauge, but they are not necessarily equivalent. Then, we answer the question about what is the consequence of a particular choice of path in DeWitt's formalism. This analysis also clarifies the implication of the gauge symmetry hidden in the concept of g.i.c. OAM. Finally, we show that the finding above offers a clear understanding about the uniqueness or non-uniqueness problem of the nucleon spin decomposition, which arises from the arbitrariness in the definition of the so-called physical component of the gauge field. (C) 2018 Elsevier Inc. All rights reserved.
资助项目	Chinese Academy of Sciences President's International Fellowship Initiative[2018VMA0030] ; Chinese Academy of Sciences President's International Fellowship Initiative[2018PM0028]
WOS关键词	QUANTUM ELECTRODYNAMICS ; MAGNETIC-FIELD ; SPIN ; POTENTIALS ; INVARIANCE ; ELECTRON ; BEHAVIOR
WOS研究方向	Physics
语种	英语
出版者	ACADEMIC PRESS INC ELSEVIER SCIENCE
WOS记录号	WOS:000431941500019
内容类型	期刊论文
源URL	[http://119.78.100.186/handle/113462/56791]
专题	中国科学院近代物理研究所
通讯作者	Wakamatsu, M.
作者单位	1.Chinese Acad Sci, Inst Modern Phys, Lanzhou 730000, Gansu, Peoples R China 2.High Energy Accelerator Res Org KEK, Inst Particle & Nucl Studies, KEK Theory Ctr, 1-1 Oho, Tsukuba, Ibaraki 3050801, Japan
推荐引用方式 GB/T 7714	Wakamatsu, M.,Kitadono, Y.,Zhang, P-M. The issue of gauge choice in the Landau problem and the physics of canonical and mechanical orbital angular momenta[J]. ANNALS OF PHYSICS,2018,392:287-322.
APA	Wakamatsu, M.,Kitadono, Y.,&Zhang, P-M.(2018).The issue of gauge choice in the Landau problem and the physics of canonical and mechanical orbital angular momenta.ANNALS OF PHYSICS,392,287-322.
MLA	Wakamatsu, M.,et al."The issue of gauge choice in the Landau problem and the physics of canonical and mechanical orbital angular momenta".ANNALS OF PHYSICS 392(2018):287-322.