In a groundbreaking advance that challenges the prevailing dominance of light-based quantum computing, researchers at the University of Chicago’s Pritzker School of Molecular Engineering have demonstrated a novel method for deterministic phase control of phonons—mechanical vibrations at the quantum scale. Moving beyond the probabilistic nature of photons traditionally used for quantum data transmission, this pioneering research paves the way for quantum computing architectures harnessing sound instead of light, offering unprecedented predictability and robustness in quantum information processing.
Quantum computing platforms have long relied on photons, or particles of light, to carry information, primarily due to their speed and low interaction with the environment. However, photons inherently suffer from randomness in their behavior, leading to probabilistic outcomes during quantum operations that challenge error correction and scalability. Addressing this limitation, a team comprising experimentalists from the Cleland Lab and theoreticians from the Jiang Group at the University of Chicago has unveiled a mechanism to exert deterministic control over the phase of phonons—quanta of mechanical vibrations—which can be thought of as the sound equivalent within the quantum realm.
Phonons, despite being less widespread in quantum computing discussions, possess advantageous qualities compared to photons. Unlike light, phonons are localized vibrational quanta, which, by virtue of their mechanical nature, do not readily leak into the vacuum of space, minimizing information loss. This quality could grant phonon-based quantum processors longer coherence times and better isolation from environmental noise. The team’s recent publication in Nature Physics details how phonons scattered off superconducting qubits can have their phase controlled deterministically, a feat that ensures quantum operations yield consistent, repeatable outcomes as opposed to the probabilistic results common in optical quantum systems.
Central to the research is the interaction between phonons and superconducting qubits—the quantum analogs of classical bits that form the foundation of quantum computation. By engineering precise coupling between these qubits and phonons, the UChicago team achieved control over the phonon phase, effectively turning phonons into reliable carriers of quantum information. This deterministic manipulation contrasts starkly with photon-based systems, where similar operations typically succeed only probabilistically, requiring complex measurement protocols to confirm success post-interaction. The novel phonon platform offers the enticing possibility of quantum operations that work “first time, every time,” potentially revolutionizing fidelity and efficiency in quantum circuits.
The implications of this deterministic control extend beyond mere manipulation. Conventional quantum systems are often hindered by probabilistic gates, leading to significant overhead in error correction and circuit complexity. By streamlining operations through deterministic phase gates mediated by phonons, quantum algorithms could be implemented with fewer resources and reduced error rates. The research also points toward scalable quantum architectures, since phonons can be confined and controlled within chip-based, solid-state devices, facilitating integration with existing quantum hardware technologies.
One limitation highlighted by the research concerns the lifetimes, or coherence times, of the phonons. Currently, engineered phonons under this protocol exhibit lifespans on the order of microseconds, restricted by their coupling to qubits—necessary for control but at the expense of rapid decay, akin to grabbing a ringing bell to silence it prematurely. Overcoming this hurdle stands as a significant next step; the team aims to extend phonon longevity by two orders of magnitude, which would enable phonons to sustain quantum information throughout more complex computational tasks.
Encouragingly, phonons decoupled from qubits theoretically possess coherence times stretching into seconds, vastly exceeding those of photons. This contrast arises because photons are electromagnetic waves that can leak into multiple external modes, while phonons remain confined in mechanical resonators without direct channels to vacuum loss. Realizing high-quality, well-isolated phononic resonators could thus unlock phonon coherence durations that fundamentally outpace light-based qubits, dramatically improving quantum memory and information retention capabilities.
In addition to phase control, the research incorporates number-resolving phonon detection—an advanced technique that counts individual phonons. This capability enriches the quantum toolbox by allowing precise measurements and manipulations of phonon quantum states, key for implementing error correction and complex quantum protocols. Such fine control over phonon populations and their quantum phases lays a robust foundation for building hybrid quantum systems that blend electronic, photonic, and phononic elements for optimized performance.
This phonon approach also dovetails with recent proposals from the same research group for novel quantum random access memory (qRAM) architectures, where compact and scalable quantum memories are crucial. By integrating deterministic phase gates and number-resolving detectors, future quantum processors could harness these phononic devices to realize fast, reliable memory and logic units essential for large-scale quantum computation.
Professor Andrew Cleland, leading the experimental effort, expressed cautious optimism about the phononic future. While acknowledging that photons remain dominant in current quantum computing efforts, Cleland emphasized that deterministic phonon platforms may present superior routes to predictability and scalability, particularly for chip-integrated, solid-state quantum technologies. Meanwhile, theoretical insights from Professor Liang Jiang underscore the broader field’s progress, noting rapid advancements in quantum phononics, including new architectures enabling compact devices with improved integrability.
Ultimately, this research heralds a transformative shift in quantum computing paradigms, replacing uncertainty with determinism at the quantum hardware level by leveraging the mechanical nature of sound. As the field advances toward extending phonon lifetimes and integrating these effects into fully coherent quantum processors, the vision of robust, scalable, and efficient quantum machines operating at the sound of their own quantum vibrations comes closer to reality.
Subject of Research: Quantum computing with deterministic phase control of phonons
Article Title: Acoustic phonon phase gates with number-resolving phonon detection
News Publication Date: 18-Sep-2025
Web References: https://doi.org/10.1038/s41567-025-03027-z
Image Credits: UChicago Pritzker School of Molecular Engineering / Joel Wintermantle
Keywords: Quantum computing
