# Bell's theorem for temporal order

### APA

Brukner, Č. (2017). Bell's theorem for temporal order. Perimeter Institute. https://pirsa.org/17110045

### MLA

Brukner, Časlav. Bell's theorem for temporal order. Perimeter Institute, Nov. 15, 2017, https://pirsa.org/17110045

### BibTex

@misc{ pirsa_PIRSA:17110045, doi = {10.48660/17110045}, url = {https://pirsa.org/17110045}, author = {Brukner, {\v{C}}aslav}, keywords = {Quantum Gravity, Other}, language = {en}, title = {Bell{\textquoteright}s theorem for temporal order}, publisher = {Perimeter Institute}, year = {2017}, month = {nov}, note = {PIRSA:17110045 see, \url{https://pirsa.org}} }

Časlav Brukner Institute for Quantum Optics and Quantum Information (IQOQI) - Vienna

## Abstract

In general relativity causal relations between any pair of events is uniquely determined by locally predefined variables - the distribution of matter-energy degrees of freedom in the events' past light-cone. Under the assumption of locally predefined causal order, agents performing freely chosen local operations on an initially local quantum state cannot violate Bell inequalities. However, superposition of massive objects can effectively lead to "entanglement" in the temporal order between groups of local operations, enabling the violation of the inequalities. This shows that temporal orders between events can be "indefinite" in non-classical space-times.