Single-Photon Superradiance and Subradiance in Helical Quantum Arrays Enable Tunable Decay Control in Two-Level Systems

The collective behaviour of light-emitting quantum systems holds immense promise for advancements in quantum technologies, and researchers are continually seeking ways to control and enhance these interactions. Hamza Patwa and Philip Kurian, both from Howard University, now present a detailed theoretical investigation into how the arrangement of these quantum systems affects their collective light emission. Their work explores both superradiance, where light emission is dramatically amplified, and subradiance, where it is suppressed, within helical structures. By developing new analytical models, they demonstrate how the geometry of these arrangements influences these effects and, crucially, show strong agreement between their theoretical predictions and existing models of complex biomaterials like protein fibres, paving the way for novel quantum devices and potentially flexible platforms for quantum information processing.

Collective Light-Matter Interactions in Biological Systems

This research investigates how collective light-matter interactions occur within biological systems, focusing on structures like microtubules and neuroprotein networks. Scientists demonstrate that these structures can exhibit superradiance and subradiance, quantum phenomena where the collective behavior of many molecules dramatically alters how light is emitted and absorbed. The study explores how these effects may enhance light harvesting, photon sensing, and information processing within living organisms. A key finding is the identification of extensive networks of tryptophan, an amino acid, within these structures that exhibit ultraviolet superradiance, suggesting a mechanism for UV light protection and energy transfer.

Researchers highlight the importance of the collective Lamb shift, a quantum effect that modifies the energy levels of molecules and influences the strength and duration of superradiance. The study reveals how the geometry and topology of these biological structures influence the emergence of superradiant states, with cylindrical microtubule structures particularly conducive to robust superradiance. Furthermore, the research investigates how chirality influences superradiance, suggesting that helical structures can exhibit unique light-matter interactions. The authors connect these findings to the quantum capacity of life, suggesting that these collective light-matter effects may contribute to the efficiency and information processing capabilities of living systems. They also explore the possibility that these superradiant states could be harnessed for highly sensitive single-photon detection, and that these findings shed light on how biological structures efficiently harvest light energy and protect themselves from harmful UV radiation. This research could inspire the development of new technologies for light harvesting, photon sensing, and quantum information processing.

Collective Emission from Linear and Helical Arrays

Scientists developed a rigorous analytical approach to understand collective emission from arrangements of two-level systems, building upon foundational work from 1954. The study derives expressions for collective decay rates and Lamb shifts when a single quantum emitter interacts with continuous distributions of these systems arranged on infinite lines and helices. This work extends previous solutions for cylinders, spheres, and spheroids by investigating these additional geometries, crucial for modeling realistic physical systems. Researchers specifically addressed the challenge of accurately describing superradiance, where emission is enhanced, and subradiance, where it is suppressed, relative to single emitters.

To achieve this, the team formulated an equation describing the time evolution of the probability amplitude of excitation within the collective of two-level systems. Solving this equation involves integrating over the volume occupied by the emitters, accounting for their density and the interaction between them. The approach utilizes a mathematical technique involving Fourier transforms to simplify the integral and obtain a solvable eigenvalue equation, revealing the collective decay rate and Lamb shift. Further extending this analysis, scientists investigated the helical geometry, relevant to biological structures like proteins and nucleic acids.

The analytical solution for the helix allows for estimations of the maximally superradiant state, the thermally averaged collective decay rate, and the percentage of trapped states. By comparing these analytical estimates with numerical results obtained from models of protein fibers, the team demonstrates excellent agreement, validating the accuracy of their approach. The study’s findings bridge different theoretical formalisms for superradiance and provide insights for engineering devices utilizing quantum optical effects for applications like error correction and quantum memories, motivating the development of flexible platforms for quantum information processing based on the intrinsic helical geometries found in biomatter.

Collective Emission on Lines and Helices

Scientists achieved a comprehensive understanding of collective light emission from arrangements of two-level systems, building upon foundational work from 1954. The research team derived novel analytical expressions for collective decay rates and Lamb shifts, examining the interaction of a single photon with continuous distributions of these systems arranged on an infinite line and an infinite helix. These solutions allow for detailed analysis of superradiance, where emission is enhanced, and subradiance, where it is suppressed, relative to single emitters. The team’s calculations reveal how the arrangement of emitters impacts collective behavior.

For the infinite helix, the maximally superradiant state occurs when a specific condition is met, while trapped states develop under different circumstances. The maximally superradiant state exhibits a diverging collective Lamb shift, a key indicator of strong collective effects. These analytical solutions provide a means to estimate superradiance and subradiance in realistic protein fibers, structures where helical geometries are prevalent. Measurements confirm excellent agreement between the analytical estimates and numerical results for sparse arrangements of emitters within protein fibers, despite differences in the inclusion of short and intermediate-range interaction terms between the models. The research bridges theoretical gaps between different formalisms used to describe superradiant matter, aiding the engineering of helical devices for quantum computing applications, including superradiant error correction and subradiant memories. This work motivates the discovery and creation of flexible platforms for quantum information processing, leveraging the intrinsic helical geometries found in biomatter.

Helical Geometry Dictates Quantum Emission Patterns

This work presents novel analytical solutions describing the collective behavior of light emitted from arrangements of quantum systems, specifically two-level systems. Researchers derived expressions for how a single photon interacts with continuous distributions of these systems arranged on infinite lines and helices, comparing these results to those obtained from cylindrical and discrete arrangements. The analysis reveals how geometric parameters, such as helical pitch and radius, influence the emergence of superradiant and subradiant states. Importantly, the team demonstrated agreement between their analytical predictions and numerical models of realistic protein fibers, suggesting that the helical structure of these biomaterials may be finely tuned to maximize quantum optical effects.

They found that specific parameter regimes, characterized by small helical pitch and radius, promote enhanced emission in the thermal average, a finding supported by experimental observations of superradiance in microtubules. The study also highlights the relationship between the topological dimension of these structures and the number of variables needed to fully describe them. The authors acknowledge that their models rely on idealized infinite structures, and further research is needed to fully account for the finite size and imperfections of real-world systems. Future work may focus on extending these analytical techniques to more complex geometries and exploring the potential of these findings for developing novel quantum technologies, including superradiant error correction and subradiant memories, as well as flexible platforms for quantum information processing using biomatter.