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SUMMARY:A Semantics for Counterfactuals in Quantum Causal Models - Eric Ca
 valcanti\, Griffith University
DTSTART:20230505T110000Z
DTEND:20230505T120000Z
UID:TALK196021@talks.cam.ac.uk
CONTACT:Damian Pitalua-Garcia
DESCRIPTION:We introduce a formalism for the evaluation of counterfactual 
 queries in the framework of quantum causal models\, by generalising the th
 ree-step procedure of abduction\, action\, and prediction in Pearl's class
 ical formalism of counterfactuals. To this end\, we define a suitable exte
 nsion of Pearl's notion of a "classical structural causal model"\, which w
 e denote analogously by "quantum structural causal model". We show that ev
 ery classical (probabilistic) structural causal model can be extended to a
  quantum structural causal model\, and prove that counterfactual queries t
 hat can be formulated within a classical structural causal model agree wit
 h their corresponding queries in the quantum extension - but the latter is
  more expressive. Counterfactuals in quantum causal models come in differe
 nt forms: we distinguish between active and passive counterfactual queries
 \, depending on whether or not an intervention is to be performed in the a
 ction step. This is in contrast to the classical case\, where counterfactu
 als are always interpreted in the active sense. As a consequence of this d
 istinction\, we observe that quantum causal models break the connection be
 tween causal and counterfactual dependence that exists in the classical ca
 se: (passive) quantum counterfactuals allow counterfactual dependence with
 out causal dependence. This illuminates an important distinction between c
 lassical and quantum causal models\, which underlies the fact that the lat
 ter can reproduce quantum correlations that violate Bell inequalities whil
 e being faithful to the relativistic causal structure. (This talk is based
  on arXiv:2302.11783.)
LOCATION:Zoom
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