论文标题

使用猫状态违反二分的leggett-garg和宏观铃铛不平等:区分弱和确定性的宏观现实主义

Bipartite Leggett-Garg and macroscopic Bell inequality violations using cat states: distinguishing weak and deterministic macroscopic realism

论文作者

Thenabadu, Manushan, Reid, M. D.

论文摘要

我们考虑对Leggett-Garg的大分现实主义和宏观现实主义的测试,在这种现实主义中,对于空格分离的测量值,宏观的宏观局部性是合理的。我们根据自旋$ 1/2 $本征态和Gedanken实验对微观Qubits的铃铛和Leggett-Garg实验进行了映射,以基于两个宏观上不同的相干状态(CAT状态)进行宏观Qubits的Gedanken实验。在此映射中,船尾grach Analyzer的统一旋转是通过交互$ h =ω\ hat {n}^{4} $实现的,其中$ \ hat {n} $是Quanta的数量。通过调整交互时间,一个人可以改变测量设置。因此,我们预测在宏观制度中对leggett-garg和贝尔不平等的违规行为,在这种宏观方向上,粗粒度测量$ \ hat {m} $仅需要区分两个宏观截然不同的相干状态。为了解释违规行为,我们区分了宏观现实主义的微妙定义。确定性的宏观现实主义(DMR)在分析仪创建的统一旋转之前,对测量$ \ hat {m} $进行了确定的结果,并因违法行为而否定。较弱的宏观现实主义(WMR)对在单一旋转后在叠加额$ψ_{pointer} $中制备的系统假设了一个确定的结果。我们发现WMR可以被视为与违规行为一致。呈现了一个模型,其中WMR所持的模型,并在整个统一动力学过程中出现了宏观违规。最后,我们指出一个EPR型悖论,在测量$ \ hat {m} $之前对系统的弱宏观描述与量子力学的完整性不一致。

We consider tests of Leggett-Garg's macrorealism and of macroscopic local realism, where for spacelike separated measurements the assumption of macroscopic noninvasive measurability is justified by that of macroscopic locality. We give a mapping between the Bell and Leggett-Garg experiments for microscopic qubits based on spin $1/2$ eigenstates and gedanken experiments for macroscopic qubits based on two macroscopically distinct coherent states (cat states). In this mapping, the unitary rotation of the Stern-Gerlach analyzer is realized by an interaction $H=Ω\hat{n}^{4}$ where $\hat{n}$ is the number of quanta. By adjusting the time of interaction, one alters the measurement setting. We thus predict violations of Leggett-Garg and Bell inequalities in a macroscopic regime where coarse-grained measurements $\hat{M}$ need only discriminate between two macroscopically distinct coherent states. To interpret the violations, we distinguish between subtly different definitions of macroscopic realism. Deterministic macroscopic local realism (dMR) assumes a definite outcome for the measurement $\hat{M}$ prior to the unitary rotation created by the analyser, and is negated by the violations. Weak macroscopic realism (wMR) assumes a definite outcome for systems prepared in a superposition $ψ_{pointer}$ of two macroscopically-distinct eigenstates of $\hat{M}$, after the unitary rotation. We find that wMR can be viewed as consistent with the violations. A model is presented, in which wMR holds, and for which the macroscopic violations emerge over the course of the unitary dynamics. Finally, we point out an EPR-type paradox, that a weak macro-realistic description for the system prior to the measurement $\hat{M}$ is inconsistent with the completeness of quantum mechanics.

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