arXiv subjects

Yehuda Roth

Publications and source records attributed to Yehuda Roth.

4 recordsLinked to original sources

arXiv2026

Identity and Self as Physical Signatures of Life in Dictyostelium and Multicellular Systems

In previous work we sought to address the fundamental question ``What is life?''. Building on that conceptual foundation, we here integrate traditional criteria for living systems with our recent proposals on physical identity and self, and apply them to concrete biological cases. We suggest that life can be characterized as the preservation of a well-defined identity ``at all costs'' together with the presence of a physically grounded self, and we show how this perspective illuminates the organization and social behavior of Dictyostelium and other multicellular systems.

physics.bio-ph↗

arXiv2026

Fock-Space Formulation of the Lifetime of a Unicellular Organism

What is life? In this work, we take life to mean a dynamical tendency to conserve identity for as long as possible. For a single bacterium, identity is carried by its chromosomal DNA code, so the bacterium is alive precisely insofar as it actively maintains a well-defined chromosomal configuration over time and can, in principle, replicate this configuration into progeny. For a multicellular organism, many cells share essentially the same DNA code and behave as a single coherent entity; in that case, life corresponds to the persistence of a common genetic identity across the cellular ensemble, rather than to the survival of any particular cell. Cell duplication in multicellular organisms likewise serves to maintain this dynamical tendency to conserve identity over time. In previous studies we implemented this idea at the multicellular and colonial scale using a classical notion of coherence, in which an organism is represented by a single nonseparable state over the DNA codes of its constituent cells, while a colony is describable as a separable ensemble. Here we apply the same principle to the simplest possible case, a single bacterium, and show that its biological identity can be identified with the coherence of its chromosomal DNA code within an abstract state space. We then introduce a Fock-space representation in which bacteria carrying given codes occupy fermionic modes, and replication, repair, and death are realized as elementary operators acting on these modes. Within this framework we define the lifetime of a unicellular organism as the integral coherence time of a code-occupation autocorrelation function and, in a minimal Markovian model, obtain a compact expression in which the lifetime coincides with the inverse decay rate of the corresponding identity mode.

physics.bio-ph↗

arXiv2026

Classical Coherence and Biological Aging

In previous work it was argued that the cells of a multicellular organism form a classically coherent system and that such coherence is essential for life. Here we make this claim precise by introducing an explicit classical formalism in which a many-cell system is represented by a single state vector in an abstract DNA code space. Using Dirac's bra-ket notation purely as a compact representation of classical states, we construct an analogue of the center-of-mass coordinate that encodes the organismal identity and show how a common genetic code shared by all cells corresponds to a coherent phase in this space. We then map this structure onto DNA sequence space by introducing a classical Biological Hamiltonian whose generalized coordinates encode DNA codes and their cell-wise distribution, so that the organismal identity is represented by a global code state rather than by individual molecular constituents. Within this framework we define a time-dependent maintenance operator with code-correcting and code-breaking terms, weighted by coefficients $A(t)$ and $B(t)$, which captures the balance between restorative dynamics and environment-induced damage to the code. Aging is described as a slow drift in these control parameters: as $A(t)$ decreases and $B(t)$ increases, the identity state becomes less stable and the organism moves from robust code coherence to stochastic code variability. In this picture, death appears as a transition in which the global identity state can no longer be maintained.

physics.bio-ph↗

arXiv2026

Classical Coherence Distinguishes Organisms from Colonies

What distinguishes a multicellular organism from a colony? In the first scenario, individual cells belong to the whole; their function is defined only within the organismal context. In a bacterial colony, each cell retains autonomy; the collective is merely a sum of separable parts. This distinction parts that belong to a unified whole versus parts that remain independent is precisely the definition of coherence in physics: a system described by a single state vector. We introduce a framework for classical coherence in biological systems. Unlike quantum coherence, which is fragile and decoheres on picosecond timescales in warm In environments, classical coherence is actively sustained by metabolic work. We construct this framework by analogy to the center of mass coordinate of a many body system: a collective mode that encodes the state of the whole. Translating this to DNA sequence space, we define a Lagrangian formalism where genetic sequences play the role of coordinates and mutation rates represent velocities. The resulting Euler-Lagrange equations yield a collective coordinate representing organismal coherence. A key prediction of our model is that coherent organisms exist in a superposition of cellular configurations that collapse upon measurement. This produces broad variance in infection outcomes across identically prepared samples, whereas incoherent colonies yield consistent, repeatable responses. To verify this prediction, we propose an experimental test using Dictyostelium discoideum, whose cells can exist either as unicellular amoebae or as multicellular slugs. Infecting both states with the same virus and measuring the distribution of Infected cells will directly validate or falsify our coherence hypothesis.

physics.bio-ph↗