Single-photon superradiance and subradiance in helical collectives of quantum emitters
Hamza Patwa, Philip Kurian · Physical Review A · 2026
Collective emission of light from distributions of two-level systems was first predicted in 1954 by Robert Dicke, who showed that when N quantum emitters absorb photons, their collective radiative decay rate can be significantly enhanced (superradiance) or suppressed (subradiance) relative to the single-emitter decay rate. In this work, we derive analytical expressions for the collective decay rates and collective Lamb shifts for the coherent interaction of a single photon with topologically one-dimensional, continuous distributions of quantum two-level systems: an infinite line and an infinite helix. We compare our solution with arrangements where the distribution of transition dipole vector emitters is discrete rather than continuous, and when short- ( 1 / r 3 ), intermediate- ( 1 / r 2 ), and long-range ( 1 / r ) interaction terms are included. We conduct a detailed comparison of our results averaging out polarization effects, with eigensolutions of similar systems maintaining the dot product between transition dipole vectors and the electric field, finding that the thermally averaged collective decay rate is enhanced in both approaches. Our analytical solution for the helix is then used to make order-of-magnitude estimates of the maximally superradiant state, thermally averaged collective decay rate, and percentage of trapped states in helical architectures of molecular quantum emitters in protein fibers. Given the inclusion of short- and intermediate-range interaction terms in our numerical models for realistic protein fiber architectures and the averaging out of polarization effects in our analytical solution, these results show excellent agreement for sparse arrangements of emitters. Our work thus bridges the theoretical gap between different formalisms for treating superradiant matter distributions, aids the engineering of helical devices to harness quantum optical effects for computing with superradiant error correction and subradiant memories, and motivates the discovery and creation of flexible platforms for quantum information processing using the intrinsic helical geometries of biomatter.