pAdic physics involves two only partially understood questions.
 Is there a duality between real and padic physics? What is its precice mathematic formulation? In particular, what is the concrete map padic physics in long scales (in real sense) to real physics in short scales? Can one find a rigorous mathematical formulation of canonical identification induced by the map p→ 1/p in pinary expansion of padic number such that it is both continuous and respects symmetries.
 What is the origin of the padic length scale hypothesis suggesting that primes near power of two are physically preferred? Why Mersenne primes are especially important?
A possible answer to these questions relies on the following ideas inspired by the model of Shnoll effect. The first piece of the puzzle is the notion of quantum arithmetics formulated in nonrigorous manner already in the model of Shnoll effect.
 Quantum arithmetics is induced by the map of primes to quantum primes by the standard formula. Quantum integer is obtained by mapping the primes in the prime decomposition of integer to quantum primes. Quantum sum is induced by the ordinary sum by requiring that also sum commutes with the quantization.
 The construction is especially interesting if the integer defining the quantum phase is prime. One can introduce the notion of quantum rational defined as series in powers of the preferred prime defining quantum phase. The coefficients of the series are quantum rationals for which neither numerator and denominator is divisible by the preferred prime.
 pAdicreal duality can be identified as the analog of canonical identification induced by the map p→ 1/p in the pinary expansion of quantum rational. This maps maps padic and real physics to each other and real long distances to short ones and vice versa. This map is especially interesting as a map defining cognitive representations.
Quantum arithmetics inspires the notion of quantum matrix group as counterpart of quantum group for which matrix elements are ordinary numbers. Quantum classical correspondence and the notion of finite measurement resolution realized at classical level in terms of discretization suggest that these two views about quantum groups are closely related. The preferred prime p defining the quantum matrix group is identified as padic prime and canonical identification p→ 1/p is group homomorphism so that symmetries are respected.
 The quantum counterparts of special linear groups SL(n,F) exists always. For the covering group SL(2,C) of SO(3,1) this is the case so that 4dimensional Minkowski space is in a very special position. For orthogonal, unitary, and orthogonal groups the quantum counterpart exists only if quantum arithmetics is characterized by a prime rather than general integer and when the number of powers of p for the generating elements of the quantum matrix group satisfies an upper bound characterizing the matrix group.
 For the quantum counterparts of SO(3) (SU(2)/ SU(3)) the orthogonality conditions state that at least some multiples of the prime characterizing quantum arithmetics is sum of three (four/six) squares. For SO(3) this condition is strongest and satisfied for all integers, which are not of form n= 2^{2r}(8k+7)). The number r_{3}(n) of representations as sum of squares is known and r_{3}(n) is invariant under the scalings n→ 2^{2r}n. This means scaling by 2 for the integers appearing in the square sum representation.
 r_{3}(n) is proportional to the so called class number function h(n) telling how many nonequivalent decompositions algebraic integers have in the quadratic algebraic extension generated by (n)^{1/2}.
The findings about quantum SO(3) suggest a possible explanation for padic length scale hypothesis and preferred padic primes.
 The basic idea is that the quantum matrix group which is discrete is very large for preferred padic primes. If cognitive representations correspond to the representations of quantum matrix group, the representational capacity of cognitive representations is high and this kind of primes are survivorsâ€Ť in the algebraic evolution leading to
algebraic extensions with increasing dimension.
 The preferred primes correspond to a large value of r_{3}(n). It is enough that some of their multiples do so (the 2^{2r} multiples of these do so automatically). Indeed, for Mersenne primes and integers one has r_{3}(n)=0, which was in conflict with the original expectations. For integers n=2M_{m} however r_{3}(n) is a local maximum at least for the small integers studied numerically.
 The requirement that the notion of quantum integer applies also to algebraic integers in quadratic extensions of rationals requires that the preferred primes (padic primes) satisfy p=8k+7. Quite generally, for the integers n=2^{2r}(8k+7) not representable as sum of three integers the decomposition of ordinary integers to algebraic primes in the quadratic extensions defined by (n)^{1/2} is unique. Therefore also the corresponding quantum algebraic integers are unique for preferred ordinary prime if it is prime also in the algebraic extension. If this were not the case two different decompositions of one and same integer would be mapped to different quantum integers. Therefore the generalization of quantum arithmetics defined by any preferred ordinary prime, which does not split to a product of algebraic primes, is welldefined for p=2^{2r}(8k+7).
 This argument was for quadratic extensions but also more complex extensions defined by higher polynomials exist. The allowed extensions should allow unique decomposition of integers to algebraic primes. The prime defining the quantum arithmetics should not decompose to algebraic primes. If the algebraic evolution leadis to algebraic extensions of increasing dimension it gradually selects preferred primes as survivors.
For details and background see the new chapter Quantum Arithmetics and the Relationship between Real and pAdic Physics.
