9 papers
A microcanonical approach to criticality in the mean-field model: evidence of intrinsic microcanonical structure before the thermodynamic limit
Loris Di Cairano, Roberto Franzosi
Collective critical behavior is often identified with thermodynamic nonanalyticities and divergences emerging only in the infinite-size limit. Here we adopt a complementary viewpoi…
The geometric origin of criticality: a universal mechanism in mean-field rotor Hamiltonians
Loris Di Cairano
We introduce a universal criterion for criticality in mean-field rotor Hamiltonians based on the geometric structure of the constant-energy shell. Rather than characterizing the on…
The Constrained Origin of Canonical and Microcanonical Ensembles in Quantum Theory
Loris Di Cairano
In quantum theory, equilibrium statistical mechanics is usually formulated through the canonical ensemble, whose privileged status is tied to the Euclidean continuation of time evo…
Criticality Beyond Nonanalyticity: Intrinsic Microcanonical Signatures of Phase Transitions
Loris Di Cairano
Phase transitions are conventionally defined by nonanalyticities of thermodynamic potentials in the thermodynamic limit. In this Letter, we show that the singularity is not the def…
Non-equilibrium quantum field theory of the free-electron laser in Keldysh formalism
Loris Di Cairano
We develop a non-equilibrium quantum field theory of the free-electron laser based on the Preparata model, using the real-time Keldysh formalism. Starting from a microscopic Lagran…
Phase Transitions as Emergent Geometric Phenomena: A Deterministic Entropy Evolution Law
Loris Di Cairano
We show that thermodynamics can be formulated naturally from the intrinsic geometry of phase space alone-without postulating an ensemble, which instead emerges from the geometric s…
Secret Entanglement, Public Geometry. Quantum Cryptography from a Geometric Perspective
Loris Di Cairano
Can a secret be hidden not in which quantum state is prepared, but in the way that state \emph{moves} through its space of possibilities? Motivated by this question, we propose an…
Geometric Entanglement Entropy on Projective Hilbert Space
Loris Di Cairano
Entanglement for pure bipartite states is most commonly quantified in a state-by-state manner to each pure state of a bipartite system a scalar quantity, such as the von Neumann en…
The specific heat anomaly stems from a third-order phase transition in the 2D lattice sine-Gordon model
Loris Di Cairano, Alexandre Tkatchenko
The specific heat anomaly (SHA) is broadly observed in statistical mechanics, appearing as a smooth, system-size-independent peak in the specific heat, in contrast to the singular…