PT Physics
Time is not the engine: it is read from the slope of persistence
PT proposes a radical reading of time: temporal order is not added to the fundamental structure, it is read from the information geometry carried by that structure.
If PT is correct, time is not what the universe computes in. It is the physical coordinate read when persistence mechanics carries a Fisher metric of Lorentzian signature.
Not an outside metronome
The sieve does not unfold under an already-existing clock: the clock appears when sieve geometry has a timelike direction.
A depth reading
$\mu$ behaves like a depth of reading; when $g_{00}<0$, that depth becomes a measurable timelike direction.
Proper time resists
One may change the reading scale, but not proper durations $\tau$ or the observables that depend on them.
L1
A clock that has already finished ticking
The most faithful image is the one used in the monograph: the sieve is like a clock that has already finished ticking. Primes are not produced one after another; the whole arithmetic hierarchy is there at once.
Still, we can read it layer by layer: parity, then $p=3$, then $p=5$, then $p=7$, and so on. That succession is not physical time yet. It is a logical order of dependence, like pages in a book that is already written: they exist together, even if we read them one after another.
Time appears when this hierarchy receives a geometry. The Fisher metric of the sieve selects an internal coordinate, $\mu$, and when its component $g_{00}$ becomes negative, that coordinate becomes timelike in the relativistic sense.
Why? Because a metric classifies directions. The three spatial directions of the sieve contribute like ordinary distances, with a positive sign. If the $\mu$ direction contributes with the opposite sign, it is no longer one more spatial distance: it becomes the direction that separates states by proper duration. That is exactly the difference between geometry of space and geometry of spacetime.
In plain language: the sieve does not unfold in time; our reading of the sieve, made metric by Fisher geometry, becomes time. The measurable duration is not bare $\mu$, but proper time $d\tau=\sqrt{|g_{00}|}\,d\mu$.
So “before time” is not a chronological before. Asking what came before this reading is like asking what lies north of the North Pole: the question uses a coordinate beyond the domain where that coordinate has meaning.
From logical hierarchy to proper time
The sieve layers are not instants. The orange arrow is only the reading order. Physical time begins when Fisher geometry makes that reading timelike, then measurable as $\tau$.
Why $\mu$ alone is not a clock
The slider keeps $d\mu=1$ and changes only $|g_{00}|$. Proper duration changes: in PT, the physical object is $d\tau$, not bare depth.
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La même profondeur de lecture donne une durée différente selon la pente métrique.
L2
Physical architecture: from depth to proper time
The monograph identifies the spacetime metric with the Fisher metric of the sieve. In that metric, the component $g_{00}$ becomes negative beyond a threshold: this is the appearance of Lorentzian signature $(-,+,+,+)$.
The decisive point is the relative sign. The Fisher blocks associated with the active primes $3,5,7$ give three positive spatial contributions. The curvature of the $\mu$ direction gives $g_{00}=-|g_{00}|$. The interval then becomes $ds^2=-|g_{00}|d\mu^2+\sum_p a_p^2dx_p^2$: displacements in $\mu$ no longer add as spatial length, they define proper duration.
Physical time is therefore not postulated. It is defined as proper time: $\tau = \int\sqrt{|g_{00}|}\,d\mu$. The variable $\mu$ gives a coordinate, but observables depend on $\tau$, not on the chosen coordinate name.
$\mu$ is a sieve-depth coordinate; $\tau$ is what a physical clock measures. PT is not merely saying “call $\mu$ time”; it says the metric forces a direction in which proper durations become defined.
The arrow of time then receives an informational reading. It is not a mysterious flow added to the world; it is the stable orientation along which persistence structure becomes readable, measurable, and irreversible for internal observables.
- $\mu$ measures sieve depth/scale.
- $g_{00}<0$ selects a timelike direction.
- $\tau$ is invariant: it carries the physical content.
- The arrow comes from monotone growth of information structure.
L3
Technical demonstration: signature, proper time, rigidity
The relativity chapter treats $\mu \leftrightarrow \tau$ structurally: the spacetime metric is a spectral invariant of the transfer matrices $\{T_m\}$, and $\mu$ is the unique coordinate producing the time component.
Time Rigidity then shows that $\tilde\mu=f(\mu)$, for any smooth strictly monotone reparametrization, preserves signature, proper time, and the observables $H_0$, $\Omega_\Lambda$, $q_0$, and $G_{\mu\nu}$.
Technically, the persistence potential $S(\mu)=-\ln\alpha_{EM}(\mu)$ gives a metric of the form $ds^2=-|S^{\prime\prime}|d\mu^2+\sum_p(S^{\prime}_p)^2dx_p^2$. The negative sign on the $d\mu^2$ term is not decorative: it turns a persistence scale into a Lorentzian time coordinate.
The physical content is therefore invariant under time-gauge changes. One may rename the coordinate, but not the proper durations, directional Hubble rates, or Einstein equations derived from it.
- Threshold: $g_{00}<0$ for $\mu>\mu_c$ in chapter 13.
- Proper time: $d\tau=\sqrt{|g_{00}|}\,d\mu$.
- Rigidity: $\tilde\mu=f(\mu)$ does not change observables.
- Arrow: the physical direction is fixed by growth of persistence/entropy in the PT dictionary.
Technical demonstration
- Start from the statistical family of the sieve. By Cencov uniqueness, the monotone metric compatible with information-non-creating transformations is the Fisher metric $g^F$.
- On the active sector $p\in\{3,5,7\}$, CRT decomposition diagonalizes the contributions: spatial scale factors are read as $a_p=\gamma_p/\mu$. A scale coordinate $\mu$ remains.
- The persistence potential $S(\mu)=-\ln\alpha_{EM}(\mu)$ gives the time component by curvature: $g_{00}=S^{\prime\prime}(\mu)$, with line element $ds^2=-|S^{\prime\prime}|d\mu^2+\sum_p(S^{\prime}_p)^2dx_p^2$ in the Lorentzian regime.
- Chapter 13 establishes the sign change algebraically: for $\mu>\mu_c$, $g_{00}<0$. A coordinate becomes timelike not by naming, but because the metric has signature $(-,+,+,+)$.
- The measurable time is then the proper-line scalar: $d\tau=\sqrt{|g_{00}|}\,d\mu$, hence $\tau=\int\sqrt{|g_{00}|}\,d\mu$.
- For any strictly monotone reparametrization $\tilde\mu=f(\mu)$, the metric transforms as $g_{00}\mapsto g_{00}/(f^{\prime})^2$ and $d\tilde\mu=f^{\prime}d\mu$. The product $\sqrt{|g_{00}|}\,d\mu$ is unchanged.
- Observables written in terms of $\tau$ — $H_p=d\ln a_p/d\tau$, $H_0$, $q_0$, $\Omega_\Lambda$, $G_{\mu\nu}$ — are therefore invariant under the coordinate change.
In PT, physical time is not postulated. It is the metric direction forced by Fisher geometry when sieve curvature becomes Lorentzian; its observable content is proper time $\tau$, not the bare parameter $\mu$.
Sources monographie
- Preface: “The sieve does not unfold in time; time unfolds from the sieve.”
- Monograph ch. 13: General Relativity from Fisher Geometry.
- ch. 13: Time Rigidity proposition.
- ch. 24: continuum-limit dissolution and quantum-gravity scope.