This section details the step-by-step derivation of the novel z-domain Chebyshev function , starting from the classical Chebyshev function and employing a sequence of analytical transformations.
3.1. Laplace Transform of
We begin by taking the Laplace transform of the second Chebyshev function
, defined in (
1). We define its Laplace transform as
Using the linearity of the Laplace transform and the transform of a Heaviside step function (specifically,
), we evaluate the transform of each term:
This leads to the relationship between
and a sum over prime powers:
This sum is a well-known Dirichlet series, which is also precisely equal to the negative logarithmic derivative of the Riemann zeta function [
7]. Thus, we identify the relationship:
The s-domain function has poles at (from ), , (from the pole of ), and at the non-trivial zeros of .
On the basis of Weierstrass’s factorization theorem and the definition for the Gamma function due to Weierstrass, we have the product form of
in terms of its zeros, as:
Taking the logs and differentiating, we obtain the Mittag-Leffler’s expansion, as:
Taking the inverse Laplace transform, we obtain:
For
the above equation diverge. However, for positive
, we have
and
Equation (
10) is the positive part of the explicit formulas established by Weil [
6]. The derivation above provides a powerful illustration of the deep connection between prime numbers and the zeros of the Riemann zeta function. The transformation technique can be summarized in four conceptual steps.
Encoding: The raw, discrete distribution of prime powers is first encoded as a series of spikes (delta functions) on a logarithmic scale.
Transformation: The Laplace transform acts as a bridge, converting this discrete distribution into a single analytic function in the complex plane, as: .
Spectral Decomposition: In this new domain, complex analysis allows this same function to be re-expressed not in terms of primes, but as a sum over its fundamental poles, which are precisely determined by the zeros of .
Inverse Transform: The final inverse Laplace transform translates this "spectral data" of the zeros back into the original domain, revealing that the prime distribution is composed of a main growth term (from the pole at ) plus oscillatory "correction" terms dictated by the non-trivial zeros.
This process provides an explicit duality, demonstrating that the distribution of prime numbers is governed by the harmonic structure of the zeros of the zeta function.
The novelty of this approach lies not in discovering a new mathematical truth, but in a powerful translation that makes a classic result conceptually clear and accessible. While the explicit formula is traditionally derived using the abstract machinery of complex contour integration, this methodology reframes the entire problem in the language of signal processing. By treating the prime distribution as a "signal" and applying the Laplace transform, the derivation becomes a familiar exercise in systems theory. This conceptual shift demystifies the process, revealing the zeros of the zeta function to be the fundamental "resonant frequencies" that govern the seemingly chaotic structure of the primes. The true innovation is therefore explanatory: it recasts an obscure theorem into an intuitive spectral decomposition, bridging the gap between pure number theory and the world of applied science and engineering.
3.2. Explicit Formula from Contour Integration
We invoke Cauchy’s Argument Principle to relate the counting function for non-trivial zeros to a contour integral involving the completed Riemann zeta function
. Let
denote the number of non-trivial zeros of
with positive imaginary parts
. The closed contour
is chosen to encompass the critical strip
from imaginary part
to
. The integral of the logarithmic derivative of
over this contour counts all zeros within
. Given the symmetry of non-trivial zeros about the real axis, the total number of zeros enclosed by
is
. Hence,
The integrand on the right-hand side (RHS) is exactly . By Cauchy’s Argument Principle, the RHS evaluates to , which is consistent with the left-hand side (LHS).
The number of zeros
is also famously related to the argument of the
-function evaluated on the critical line. Specifically, by applying the Argument Principle over a contour enclosing the critical strip and utilizing the symmetry properties of
, one derives the standard result (see, e.g., Titchmarsh [
3]):
where the argument is defined by continuous variation from a reference point on the real axis (e.g.,
) where
. This formula holds precisely if
is not the ordinate of a zero. The term
is the imaginary part of
. Since
is real for real
s, we have
. Consequently, the difference of logarithms becomes:
Therefore, we can express the counting function as:
We now evaluate the term on the RHS using the definition of
:
Evaluating this difference at
and
, we have:
For large
, we use the asymptotic behavior of complex logarithms and the Stirling approximation for the Gamma function. The terms involving
and
simplify using
for arguments near
or
:
Additionally, Stirling’s approximation for the Gamma function logarithm yields (see, e.g., [
8]):
Substituting these approximations into the equation for
and simplifying, we obtain:
Further simplification leads to:
Thus, we can define the exact explicit Riemann-von Mangoldt zeta zeros count function formula in the
-domain [
9], as
The derivation of explicit formulas using contour integrals, particularly those relating arithmetic sums to sums over zeta zeros, can be conceptually viewed as a form of inverse transform. This method effectively "inverts" a Dirichlet series (like ) by integrating along specific contours in the complex plane, akin to inverse Laplace transforms with finite limits instead of infinite limits.
Now, the logarithm of the Riemann zeta function can be expressed through its Euler product [
7]:
Substituting this expansion into the difference term for
:
Combining these results, we obtain an explicit formula for the zero-counting function in terms of the prime harmonics, as:
3.3. The Delta-Function Density
We differentiate Equation (
21) with respect to
. The Heaviside sum on the LHS transforms into a sum of Dirac delta functions, representing the density of zeros along the imaginary axis.
Rearranging terms and dividing by
i, we obtain a precise explicit formula for the density of non-trivial zeros:
The relationship between Equation (
10) and Equation (
23) represents a profound duality, forming the mathematical core of the connection between primes and zeta zeros. The first formula, a "prime-centric" view, expresses the distribution of prime numbers as a sum over the zeros of the zeta function. It answers the question, "Where are the primes?" by using the "spectral data" of the zeta zeros. In stark contrast, the second formula provides the dual "zero-centric" view: it expresses the distribution of the heights of the zeta zeros as a sum over the prime numbers. It answers the question, "Where are the zeta zeros?" using the primes as the fundamental frequencies. This perfect reciprocity implies that the two sets of numbers—the primes and the zeta zeros—are inextricably locked together, like a signal and its Fourier transform. All the information about one set is perfectly encoded in the other. This duality is the basis for the modern perspective of number theory through physics, suggesting that the zeros are like the resonant energy levels of a quantum system whose structure is determined by the primes, which act like a classical potential.
3.4. Transformation to the z-Domain
We now apply the Laplace transform with respect to
to Equation (
23). Let
z be the Laplace variable. The Laplace transform of
is
.
To uncover a product form, we perform a manipulation by considering
z as a complex variable. Replacing
z by
and
in the above equation, we obtain two related expressions:
and
Subtracting the first of these two equations from the second, we obtain:
Noting that
by assuming
. Thus, simplifying the logarithmic term on the RHS, and multiplying the entire equation by
i and dividing throughout by 2, we obtain:
Finally, using the identity
and
, the LHS can be expressed in terms of sine, as:
3.6. Exponentiation and Definition
We now exponentiate both sides of Equation (
30) to obtain a product representation. We define the
z-domain second Chebyshev function
as:
This product form for reveals a fascinating property: its zeros are precisely located at for all prime numbers p and positive integers k. These are the logarithmic prime powers, demonstrating a direct encoding of prime number information.
Noting that the identity for was derived under the condition . To justify its validity across the entire complex plane, we invoke the principle of analytic continuation. Both the product representation of and its exponential sum form define functions that are analytic on the complex plane. Since these two analytic functions have been proven to be equal on the open right half-plane, a domain which contains limit points, the Identity Theorem for analytic functions guarantees that they must be identical everywhere. This rigorously extends the equality from the right half-plane to the entire complex plane, confirming that the function’s zeros are indeed located at .
3.7. x-domain Representation and Graphical Properties
Finally, by substituting
into the definition of
, we obtain its representation in the
x-domain:
The zeros of are thus at and (for ), which is consistent with the zeros at .
The exponential form on the RHS of (
32), given by
where
yields a real-valued function for real
x. This implies that
is always real. Its positivity depends on the sum
. The product form clearly shows that
if
for some prime
p and integer
k. This occurs when
, leading to
(for
) or
(for
). At these specific points, the sum
in the exponent must diverge to
, driving
to zero. This behavior is clearly illustrated in
Figure 1, showing sharp dips towards zero at prime power values of
x. The corresponding plot of
in
Figure 2 confirms these divergences as sharp poles towards
.