Can future observation of the living partner post-tag the past decayed state in entangled neutral K mesons?

Abstract

Entangled neutral K mesons allow for the study of their correlated dynamics at interference and decoherence times not accessible in any other system. We find novel quantum phenomena associated to a correlation in time between the two partners: The past state of the first decayed kaon, when it was entangled before its decay, is post-tagged by the result and the time of the future observation of the second decay channel. This surprising "from future to past" effect is fully observable and leads to the unique experimental tag of the K S state, an unsolved problem since the discovery of CP violation.

Entanglement, CPT and neutral kaons

“…7 These results constitute the first direct tests of T and CPT symmetries in kaon transitions. The T and CPT observables have been measured with a precision of few percent, showing no evidence of symmetry violations, while CP violation has been observed with more than 5σ significance with the observable ratio (5).…”

“…Neutral kaons produced at a φ-factory combine their peculiar flavour oscillations, charge-parity (CP) and time-reversal (T) violation, into an Einstein-Podolsky-Rosen (EPR) entangled system, revealing surprising features. [1][2][3][4][5] Here the possibility of exploiting their entanglement to make direct tests of T, CP, CPT symmetries is briefly reviewed.…”

Observation of the post-tagging effect for entangled K mesons at KLOE

“…The decay amplitude of state | to channel 1 at time 1 for particle-1 and channel 2 at time 2 for particle-2, and the corresponding observable double differential decay rate ( 1 , 1 ; 2 , 2 ) can be readily calculated using the formalism first introduced by Lee and Yang (see Refs. [1][2][3][4]):…”

“…Similarly, exploiting the 1 , 2 symmetry of the Lee-Yang approach, the past state of particle-1 immediately before its decay at time 1 is [3]:…”

A direct test of T, CP and CPT symmetries in transitions of neutral kaons with KLOE data

“…Testing the discrete symmetries of a physical system constitutes one of the most powerful tool to understand the underlying interactions and their theoretical description. The neutral kaon system at a φ-factory combines its peculiar flavour oscillations, charge-parity (CP) and timereversal (T ) violation, into an Einstein-Podolsky-Rosen (EPR) entangled system, revealing surprising features [1,2,3]. In order to realize direct tests of T , CP, CPT symmetries in neutral kaon transition processes, it is necessary to compare the probability of a reference transition with its symmetry conjugate.…”