Two Quantum Fluid Breakthroughs from July 2026: Sound-Wave Superfluid Probing and Cloud-Based Anomalous Tunneling

The method, known as Sagnac phonon interferometry, works by measuring how sound waves — or phonons — travel through a rotating superfluid. Just as the Doppler effect changes the pitch of an ambulance siren as it passes, the rotation of the superfluid shifts the phase of the sound waves, revealing the system's angular momentum , .

What it reveals:

• Cooper pairs and fermionic superfluidity: By "listening" to how sound propagates, researchers can indirectly infer the fermionic pairing mechanism — the formation of Cooper pairs — that underlies superfluidity. This pairing is the same phenomenon that drives superconductivity in certain materials, but it has been notoriously difficult to probe directly .
• Quantized circulation: The Sagnac interferometry technique provides a new way to measure quantized vortices and the circulation quantization that is a hallmark of fermionic superfluids . This is the first time such quantized circulation has been detected in a strongly correlated fermionic system using sound.

The achievement was described as opening a new window into quantum matter, where sound becomes a powerful diagnostic tool for systems that are otherwise opaque to conventional measurement .

2. Cloud-Based BEC Experiment Confirms Anomalous Tunneling

Published in Communications Physics on July 31, 2026, a study led by theoretical physicists Ippei Danshita (Kindai University) and Daichi Kagamihara (Chuo University) used Oqtant, a cloud-accessible platform for BEC experiments provided by the company Infleqtion, to remotely observe the influence of anomalous tunneling on collective excitations , . This marks the first peer-reviewed scientific result produced through the Oqtant platform .

What is anomalous tunneling?
Unlike ordinary quantum tunneling — where the probability of transmission drops as particle energy decreases — anomalous tunneling in a BEC shows the opposite behavior. Low-energy sound waves (collective excitations) are transmitted perfectly even through high barriers, with the transmission probability approaching unity at zero energy . The experimental observations matched theoretical predictions, confirming this counterintuitive effect for the first time .

Broader significance: Anomalous tunneling is predicted to occur not only in BECs but also in materials such as magnets, making this experimental confirmation a significant step for condensed matter physics .

3. The Democratization of Quantum Research

The BEC experiment represents a milestone in making advanced quantum research accessible. Traditional ultracold atom experiments require years of specialized training to build and operate, effectively barring theoretical physicists from conducting their own experimental tests . By providing a cloud-accessible platform, Oqtant allowed theorists to design and run experiments remotely without needing their own laboratory infrastructure , .

The researchers noted that this approach "holds the potential to significantly expand what theoretical physicists can do in their research" and could serve as "a powerful catalyst for the migration of other state-of-the-art experimental facilities to the cloud" . This mirrors the broader trend of cloud-based quantum computing services (e.g., from IBM and Google) and represents an emerging paradigm in which advanced experimental apparatus becomes accessible to a wider research community .

Both experiments, though independent, share a common thread: they use sound and accessible platforms to probe quantum fluids in ways that were previously impossible. Together, they represent a step forward not only in understanding superfluidity and quantum tunneling but also in reimagining who gets to perform cutting-edge physics.