D-Branes, AdS/CFT, Dynamical Uhlmann Gauge, and Stabilisation of a Closed Causal Loop Geometry

I show here that if we construct D-branes not in the form of infinite superpositions of string modes, in order to satisfy the technical condition of coherence by means of eigenstates of annihilation operators, but instead insist on an approximate but much more physical and practical definition based on phase coherence, we obtain finite (and hence realistic) superpositions of string modes that would form realistic D-branes that would encode (at least as a semiclassical approximation) various quantum properties. Re-deriving the AdS/CFT duality by starting in the pre-Maldacena limit from such realistic D-branes would lead to quantum properties on the AdS side of the duality. Causal structures can be modified in various many-particle systems, including strings, D-branes, photons, or spins; however, there is a distinction between the emergence of an effective causal structure in the inner degrees of freedom of a material, in the form of a correlation-generated effective metric, for example, in a spin liquid system, and the emergence of a causal structure in an open propagating system by using classical light. I will show how an Uhlmann gauge construction would add stability to a modified causal structure that would retain the shape of a closed causal loop. Various other ideas related to the quantum origin of the string length are also discussed and an analogy of the emergence of string length from quantum correlations with the emergence of wavelength of an electromagnetic wave from coherence conditions of photon modes is presented.