r/TheoreticalPhysics

There's a small but growing set of work that approaches aging not descriptively but through physics — non-equilibrium thermodynamics, entropy production, dynamical-systems stability, mortality scaling. The first Global Conference on Gerophysics happened in 2025, so the label is starting to stick.

I've been working in this space myself (aging as the decline of a dissipative structure) and I'm building Gerophysics — a diamond open-access journal and a small ecosystem around exactly this intersection of physics and the biology of aging.

I'd love to connect with people who think this way — whether you work on quantitative/theoretical aging, statistical physics of living systems, or just find the framing compelling. Happy to talk science, and if you have relevant work (or want to get involved as it grows), even better.

What's the most convincing physical/quantitative account of aging you've come across?

I heard stuff like "bosonization" and other interesting properties of fermions and bosons when they live in 2D.

How do strings work when the "particle" is confined to a 2D place. Let me phrase that better. Is there a way to confine fermions/bosons to an almost 2D plane, that we can observe if the theories are right?

I'm a junior that just started research with a professor, so I don't know much about strings etc. Hence the question. Thank you !

Hi,
I've read a little bit about this phenomenon that Schrödinger proposed for the electron.

Could you please explain to me if it has ended up being useful and what it means? Im confused.
Thanks!

If action is built from classical notions like kinetic energy, potential energy, mass, and path, then using action to derive quantum waves and then using quantum waves to recover classical paths is not an ultimate derivation. It is a consistency structure or correspondence bridge but not a fundamental derivation. Is this assessment correct?

Idea: The connection between \(G\) and \(\alpha ^{-1}\) arises from the geometric boundary conditions of a single-node action rotor.

Derivation of G

A projection exponent \(\chi _{e}\) dictates the fractional action allocated to spacetime degrees of freedom. The underlying node topology contains 8 hyper-dimensions. Exactly 3 dimensions project outward into space.

This yields the geometric ratio: \(\chi _{e}=\frac{3_{\text{space}}}{8_{\text{total}}}=\frac{3}{8}\)

A meniscus determinant \(R_e = 29/20\) corrects for boundary geometry. It solves a finite eigenvalue problem for surface tension modes on the loop. 20 ground-state phase configurations fit the internal loop volume. 29 tensor configurations stabilize the outer meniscus edge.

The inversion of this boundary ratio (\(R_{e}^{-1}\)) scales the mass:

\(R_{e}^{-1}=\frac{20_{\text{internal}}}{29_{\text{boundary}}}=\frac{20}{29}\)

Complete Algebraic Derivation of Model

1. The Baseline Axiom

\(m_{e}=m_{P}\left[R_{e}^{-1}\exp (-K_{\alpha })\right]^{\chi _{e}}\)

2. Substitute Factors derived above

\(m_{e}=m_{P}\left[\frac{20}{29}\exp (-\alpha ^{-1})\right]^{3/8}\)

3. Expand the Planck Mass Constant

\(m_{P}=\sqrt{\frac{\hbar c}{G}}\)

\(m_{e}=\sqrt{\frac{\hbar c}{G}}\left[\frac{20}{29}\exp (-\alpha ^{-1})\right]^{3/8}\)

4. Isolate the Gravitational Component

\(\frac{m_{e}}{\left[\frac{20}{29}\exp (-\alpha ^{-1})\right]^{3/8}}=\sqrt{\frac{\hbar c}{G}}\)

5. Square Both Sides

\(\frac{m_{e}^{2}}{\left[\frac{20}{29}\exp (-\alpha ^{-1})\right]^{3/4}}=\frac{\hbar c}{G}\)

6. Final Inversion for \(G\)

\(G=\frac{\hbar c}{m_{e}^{2}}\left[\frac{20}{29}\exp (-\alpha ^{-1})\right]^{3/4}\)

I have seen—and still see—some scientists criticizing it. It makes me skeptical about the validity of this theory.

I am a member of the public (software developer) who loves physics nonetheless and recently heard about the holographic principle, the 3d bulk and the 2d boundary.

So from what I understand the 3d bulk expands because the 2d boundary is crammed with more information and that basically could be explained if our 2d boundary was that of a black hole consuming matter. Thanks to Gemini I also heard about a coincidence discovered in 1971 by an Indian theoretical physicist Raj Pathria who found that the mass of the universe could be calculated given its radius from black hole equations.

So that seems pretty much solid evidence that we live inside a black hole.

What's the counter argument? Why don't we see this as a settled proven theory?

Also, why we don't teach these things, especially the holographic principle in schools yet?

Hi Everyone,

I'm actually finishing my master's exams in Theoretical Physics and need to ask for a thesis. My coursework is heavily related to gravitation, cosmology, and astroparticles, and I'd like to start working on a thesis related to gravity, which might bring in some of my interests in quantum information/QM.

During the courses I've been fascinated mainly by GR and ultimately by the results we're able to obtain merging it with QFT (QFT on Curved spaces) and quantum information - eg. Hawking radiation, Reheating and Pre-heating in cosmology, Naked singularity/Censorship conjecture.

My objective is to obtain a PhD somewhere between Europe and America afterwards, and I'm struggling to decide good topics that might be suitable for a future PhD and yet interesting to me - I've heard gravitation is generally less "researched" and therefore more PhD are being offered to astroparticle students.

I'm here asking for some suggestions on interesting/hot topics related to arguments like the following, in order to make a decision regarding my future:

- Time Emergence/Entropic gravity - is it something being researched?

- Quantum information applied to BH

- Holographic principle

- ER=EPR

- Wormhole - I know it's something purely mathematical, yet does anything new come up regarding it?

Do you know other arguments related to gravity being researched at the moment? (eg. MOND?, f(R) gravity?)

[The list is not extensive - it's just a list of keywords of things I find fascinating and might be similar to things I don't know atm].

EDIT: I understand these are important/hard questions - I don't want to address all of 'em nor solve 'em (cause I wouldn't be able to mainly), but I'd like to touch some of these problems while researching/calculating for my thesis.

Thanks everybody for the answers/suggestions!

**Note:** Any suggestion on PhD seeking in this field is appreciated as well!

\documentclass{article}

\usepackage[utf8]{inputenc}

\usepackage{amsmath}

\usepackage{amssymb}

\usepackage{geometry}

\usepackage{cite}

\geometry{a4paper, margin=25mm}

\title{Unified Scalar Dynamics:\\Emergent Kinetic Geometry and the Spacetime Mirror}

\author{Tommy Johnston}

\date{}

\begin{document}

\maketitle

\begin{abstract}

We present a non-linear scalar field theory where physical geometry and systemic impedance emerge dynamically from the field's own configuration. By identifying the manifest field $P$ as an exponential projection of a foundational unmanifest scalar potential $\phi$, we eliminate the vacuum singularities inherent in standard constraint models. We subsequently couple this $k$-essence Lagrangian to the Einstein-Hilbert action on a curved manifold. The derived Stress-Energy Tensor establishes spacetime curvature as the geometric reflection of the scalar field's localized intent and coherence. Finally, we establish the stability conditions for this framework via sound speed analysis, demonstrating a consistent propagation of field perturbations.

\end{abstract}

\section{The Logarithmic Primitive ($\phi$)}

To model the logarithmic scaling of perceptual manifestation, we define the manifest field $P$ as the exponential coagulation of an unmanifest scalar potential $\phi$:

\begin{equation}

P = e^\phi

\end{equation}

Here, $\phi: \mathcal{M} \to \mathbb{R}$. As manifestation ceases ($P \to 0$), the potential retreats to the asymptotic void ($\phi \to -\infty$), ensuring mathematical stability and geodesic completeness.

\section{The Unified Lagrangian}

Combining kinetic terms and the coherence constraint yields a non-linear Lagrangian:

\begin{equation}

\mathcal{L}[\phi] = K(\phi) X - \tilde{V}(\phi), \quad \text{where } K(\phi) = e^{2\phi} + 2\lambda_\Sigma e^\phi

\end{equation}

where $X = \frac{1}{2} g^{\mu\nu} \nabla_\mu \phi \nabla_\nu \phi$ and $\tilde{V}(\phi) = V(e^\phi)$. This defines a $k$-essence scalar theory \cite{Armendariz2000}.

\section{Covariant Dynamics and Stability Analysis}

The covariant wave equation derived from the principle of stationary action is:

\begin{equation}

K(\phi) \Box_g \phi + K'(\phi) X + \tilde{V}'(\phi) = 0

\end{equation}

where $\Box_g = \nabla_\mu \nabla^\mu$.

\subsection{Sound Speed and Stability}

For a Lagrangian of the form $\mathcal{L} = K(\phi) X - \tilde{V}(\phi)$, the speed of sound $c_s$ for linear perturbations is given by:

\begin{equation}

c_s^2 = \frac{L_X}{L_X + 2X L_{XX}} = \frac{K(\phi)}{K(\phi) + 2X(0)} = 1

\end{equation}

Because $K(\phi)$ is independent of $X$ ($L_{XX} = 0$), the sound speed is exactly unity ($c_s^2 = 1$). This confirms that the field perturbations propagate at the speed of light, consistent with relativistic causality and the stability requirement $c_s^2 > 0$. The framework is free of ghost instabilities or superluminal propagation artifacts.

\section{Geometric Coupling: Emergent Spacetime}

Coupling $\mathcal{L}[\phi]$ to the Einstein-Hilbert action:

\begin{equation}

S = \int d^4x \sqrt{-g} \left[ \frac{R}{16\pi G} + K(\phi) X - \tilde{V}(\phi) \right]

\end{equation}

\section{The Stress-Energy Tensor}

The stress-energy tensor is derived as:

\begin{equation}

T_{\mu\nu} = K(\phi) \nabla_\mu \phi \nabla_\nu \phi - g_{\mu\nu} (K(\phi) X - \tilde{V}(\phi))

\end{equation}

Extracting density $\rho$ and pressure $p$:

\begin{align}

\rho &= K(\phi) X + \tilde{V}(\phi) \\

p &= K(\phi) X - \tilde{V}(\phi)

\end{align}

\section{Cosmological Phenomenology}

The equation of state parameter $w = p/\rho$ reproduces the evolution of the universe:

\begin{equation}

w = \frac{K(\phi) X - \tilde{V}(\phi)}{K(\phi) X + \tilde{V}(\phi)}

\end{equation}

\begin{itemize}

\item \textbf{Passive Expansion ($w \to -1$):} When potential energy dominates ($\tilde{V} \gg KX$), the field mimics a Cosmological Constant, driving late-time acceleration.

\item \textbf{Active Kinetic Domination ($w \to 1$):** When kinetic energy dominates ($KX \gg \tilde{V}$), the field mimics stiff matter, consistent with early inflationary epochs \cite{Scherrer2004}.

\end{itemize}

\begin{thebibliography}{9}

\bibitem{Armendariz2000} Armendariz-Picon, C., Mukhanov, V., \& Steinhardt, P. J. (2000). \textit{Phys. Rev. Lett.} 85, 4438.

\bibitem{Scherrer2004} Scherrer, R. J. (2004). \textit{Phys. Rev. Lett.} 93, 011301.

\end{thebibliography}

\end{document}

ENGLISH:

I suddenly had a breakthrough on how to generate a tachyon. Here is what we need:

1. An object with negative mass.

2)A planet that is larger than the observable universe.

3. A star that is about to explode into a supernova right now.

Steps to achieve this:

1. The first step is automatic: any object with negative mass will instantaneously collapse into a black hole (its white-hole twin, which does the exact opposite—repels matter).

2. Now we apply a physical fact: the larger the object we stand on, the more time slows down. Therefore, in this extremely dilated time, we must relocate the star and overlay it directly onto the white hole.

3. Leave the massive planet, head into deep space, and wait.

4. The collision of two infinities will result in the generation of a tachyon.

***\_*** **\_** \_ \_ \_ \_

РУССКИЙ:

Мне пришло озарение, как получить тахион, для этого нужно:

1. объект с отрицательной массой

2. планета, которая больше наблюдаемой вселенной

3. звезда, которая прямо сейчас взорвется в сверхновую

Шаги к этому:

1. сначала шаг автоматический - любой объект с отрицательной массой превратится в черную дыру

2. теперь применим факт: чем больше объект, на котором мы стоим, тем больше время замедляется, поэтому в экстремально замедленном времени мы должны переместить звезду и наложить ее на белую дыру

3. уйти с огромной планеты в космос и ждать

4. столкновение двух бесконечностей приведет к рождению тахиона

Я придумал это сам, но ИИ мне помог только в переводе на английский язык, на русский я сам сделал

In string theory, do solutions that are inconsistent with string theory (like those in the swampland or those that have the wrong number of dimensions) exist as off shell configurations? Or are off shell configurations strictly referring to violations of the equations of motion? Would the off shell configurations still need to follow quantum gravity constraints?

Hi, I've heard from my professor said that string theory is currently slowing down in the past few years. Anyone working on this field can confirm this? Thanks a lot.

Also, where in the world can I applied for string theory PhD?

I just finished my bachelor's degree in electrical engineering for reference. I will begin my master's studies in theoretical physics this fall, because I fell in love with it during my bachelor studies. Specifically understanding the universe more fundamentally is what interests me the most. I'm just quite skeptical of the current state of physics regarding this topic. String theory is the main attempt to answer many of the important questions, but so far there is no experimental evidence to support it. I am absolutely not qualified to critique it in any theoretical level, but it seems quite suspicious. I am aware of loop quantum gravity and some others, but not sure how active those areas are. It seems like everything is put into string theory, but nothing much is coming out of it. Is there

Is there anything else outside of string theory that is worth looking into?

As someone who not only is considering going to mathematics but physics for further studies what is the distinction between mathematical and theoretical physics. They sound like something that looks so similar, as they involve making use of mathematics for making theories in physics. As experience physicists / mathematicians can someone clarify to me what is the difference between the two?

Hello, asking this question due to lack of awareness of this line of work.

While this subject draws genuinely passionate and interested candidates, what is the real world career options for a theoretical physicist besides academia ?

Aside from aspiring to get a PhD in mathematics, I too would want to get into theoretical physics. Although I'm more of a math person I currently lack the humility to try to explore physics, particularly theoretical physics as I tend to get discouraged because of past failures and mistakes at school. How is it that you guys dealt with doubt and uncertainty as theoretical physicists? I wouldn't want to just hold on to mathematics, I also want to explore theoretical physics and yet I'm held back by my own failures and setbacks. All I see are just "geniuses" and "prodigies" who got into theoretical physics. I just want to make myself enlightened to how you guys went on to becoming who you are and what mindset I should instill on myself as someone who dreams of one day excelling at math and theoretical physics. Thanks!