Effective approach to the problem of time: general features and examples
Effective approach to the problem of time: general features and examples
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解决时间问题的有效方法：一般特征和示例
DOI：
10.1103/physrevd.83.125023
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发表时间：
2010
影响因子：
5
通讯作者：
Artur Tsobanjan
中科院分区：
文献类型：
--
作者：
M. Bojowald;Philipp A. Hoehn;Artur Tsobanjan
量子动力学的有效方法允许在无限维经典型约束系统方面重新表述约束系统的狄拉克量子化过程。对于半经典近似，量子约束系统可以截断到有限尺寸，并通过约化相空间或规范固定方法求解。特别是，局部内部时间的经典可行性被直接推广到量子系统，克服了与半经典领域中的一般时间问题相关的主要困难。局部内部时间的关键特征和使用局部内部时间的重叠间隔修补全局解的过程被描述并通过两个量子力学的例子说明。在给定的内部时间选择中的关系演化最方便地描述和解释为在有效水平上相应的规范选择，因此，改变内部时钟基本上是通过规范变换来实现的。本文补充了[ M. Bojowald，P. A. Hohn和A. Tsobanjan Classical Quantum Gravity 28 035006（2011）]。
The effective approach to quantum dynamics allows a reformulation of the Dirac quantization procedure for constrained systems in terms of an infinite-dimensional constrained system of classical type. For semiclassical approximations, the quantum constrained system can be truncated to finite size and solved by the reduced phase space or gauge-fixing methods. In particular, the classical feasibility of local internal times is directly generalized to quantum systems, overcoming the main difficulties associated with the general problem of time in the semiclassical realm. The key features of local internal times and the procedure of patching global solutions using overlapping intervals of local internal times are described and illustrated by two quantum mechanical examples. Relational evolution in a given choice of internal time is most conveniently described and interpreted in a corresponding choice of gauge at the effective level and changing the internal clock is, therefore, essentially achieved by a gauge transformation. This article complements the conceptual discussion in [ M. Bojowald, P. A. Hohn and A. Tsobanjan Classical Quantum Gravity 28 035006 (2011)].