#### Alladi Ramakrishnan Hall

#### Frequentist-approach inspired theory of quantum random phenomena predicts signaling

#### C. S. Sudheer Kumar

##### IISER--Pune

*Consider the following problems: Why cannot we distinguish*

between x and z ensembles, each described by the same density matrix,

even though they are physically different (arXiv:1811.05472

[quant-ph])? Why do Gibbs-von Neumann entropy (which uses density

matrix description) gives wrong prediction in closed non-equilibrium

systems (arXiv:1903.11870 [cond-mat.stat-mech])? etc.

Root cause of all these problems is the a priori assumption of

existence of a probability measure (a purely mathematical quantity

unjustifiable physically), on which density matrix description rests.

But such a probability measure does not exist physically because of no

pointwise convergence of limiting relative frequency to the

theoretically assumed constant value for the probability of a random

event. Hence such an a priori assumption of a probability measure

(even though appealing intuitively) is incorrect physically. Moreover

such an a priori assumption of a probability measure is not really

necessary, even though useful for many practical purposes as it

simplifies the calculations. Hence Ockham's thesis motivates us to

drop the a priori assumption of a probability measure completely. We

consider path by path, everything is pointwise (e.g., fluctuation in

itself i.e., the actual fluctuation), no a priori probabilistic

measures (like standard deviation which is an averaged measure of

fluctuation) (arXiv: 1903.12096 [quant-ph]). Consequently we see that

all problems are fixed i.e., we can distinguish between x and z

ensembles (this leads to signaling via entangled particles), Boltzmann

entropy gives correct prediction etc.

I will also talk briefly about, going beyond Tsirelson bound and

quantum cryptography; NMR investigation of contextuality, Luders and

von Neumann measuring devices, and amplification of quantum Fisher

information via pre-correlated ancillas.

Done