In a significant development in quantum computing, scientists have successfully created a qubit that achieves “quantum coherence” at room temperature, a feat previously achievable only at temperatures close to absolute zero. Quantum coherence, a stable state allowing the observation of quantum mechanics, is typically hindered by disturbances at higher temperatures. To overcome this challenge, researchers utilized a pentacene-based chromophore embedded in a new metal-organic framework (MOF), enabling brief observation of quantum coherence at room temperature.
In classical computing, data is encoded in bits representing either 1 or 0. Quantum computers, on the other hand, utilize qubits that exist as a superposition of both states until observed. Most physical qubits create a superposition by manipulating an electron’s spin-up and spin-down positions. Quantum entanglement, linking the states of particles, allows multiple qubits to exist in various states simultaneously, potentially making quantum computers significantly more powerful than classical ones.
The new qubit employs singlet fission, a process where electrons in chromophores are excited by absorbing light and changing their spin states. Unlike previous attempts that achieved this below extremely low temperatures, the researchers used a chromophore based on pentacene hydrocarbon and trapped it in an MOF. This crystalline material restricted the dye molecule’s movement, maintaining excited electrons in an entangled state. By exposing the electrons to microwave pulses and utilizing nanopores in the crystalline structure, the researchers achieved quantum coherence in entangled quintet-state electrons for over 100 nanoseconds at room temperature.
While the breakthrough marks the first room-temperature quantum coherence of entangled quintet-state electrons, the researchers acknowledge that practical room-temperature quantum computing remains a distant goal. However, they aim to enhance stability by incorporating additional “guest” molecules or adjusting the MOF’s structure. The achievement contributes to the ongoing efforts to build qubits with quantum coherence at room temperature, potentially eliminating the need for error correction and paving the way for more advanced quantum computing in the future.
