Our \u201cstudy maps a general path towards generating a profoundly different topological quantum resource with immunity against both dark modes and dark states,\u201d the study authors note<\/a>.\u00a0<\/p>\n This development could transform how future quantum devices store and transmit information, especially in systems that deal with light and sound at the smallest scales.<\/p>\n The dilemma due to dark modes\u00a0<\/p>\n To understand the breakthrough, it is important to know the setting. The researchers were working with non-Hermitian systems\u2014a class of quantum systems that can exchange energy with their surroundings.\u00a0<\/p>\n These systems have become a hot topic because they can host unusual topological effects<\/a>. In simple terms, topology here refers to properties that remain stable even when a system is slightly disturbed, making them attractive for robust quantum technologies.<\/p>\n In such systems, particles like photons (light) or phonons<\/a> (vibrations of sound) can be guided in controlled ways\u2014for example, forced to move only in one direction.<\/p>\n \u201cTopological operations allow for various weird and fascinating phenomena, such as the buildup of chiral phases and the movement of phonons in one direction,\u201d Franco Nori, one of the study authors and a scientist at RIKEN, explained.<\/p>\n However, there\u2019s a catch. Quantum systems don\u2019t just have one mode of motion or excitation\u2014they have many. Some of these are bright modes, which interact with external signals and can be controlled.\u00a0<\/p>\n Others are dark modes, which are completely decoupled. They don\u2019t respond to the driving field at all\u2014almost like hidden gears in a machine that you cannot touch.<\/p>\n These dark modes create a serious problem. When they are present, \u201cboth conversion between different modes and the topological transfer of phonons break down, and these effects can\u2019t be restored by the usual measures,\u201d Nori explained.<\/p>\n This means no controlled transfer of energy, no directional motion, and no useful quantum operations. Traditional fixes\u2014like tweaking the system\u2019s parameters\u2014don\u2019t work because the dark modes remain fundamentally disconnected.<\/p>\n The way to outsmart dark modes<\/p>\n The RIKEN team took a different approach. Instead of trying to eliminate dark modes, they decided to reprogram them. They introduced carefully designed artificial quantum<\/a> information into the system.\u00a0<\/p>\n While the term sounds abstract, the idea is straightforward. They added specific quantum inputs that change how different modes interact. This engineering effectively forces dark modes to temporarily couple with the system\u2014turning them into bright modes.<\/p>\n![\"\"](\"https:\/\/www.newsbeep.com\/au\/wp-content\/uploads\/2026\/04\/dark-modes-and-bright-modes.jpg\" "\\"Dark")
An illustration of a quantum system with the two phonon modes. Source: RIKEN Center for Quantum Computing<\/a><\/p>\n