Refining Control of Quantum Memories
Quantum computers need ways to store and control fragile quantum information without introducing too many errors. In one promising approach, the information is held in a quantum memory made of a superconducting microwave cavity. It is then manipulated by a quantum processor implemented as a superconducting circuit called a transmon. Unfortunately, this error-saving approach is itself error prone. Inevitable imperfections in the transmon induce errors in the cavity when the two components interact. Now Srivatsan Chakram of Rutgers University in New Jersey and his colleagues have demonstrated a way to efficiently control the cavity’s stored information while minimizing these transmon-mediated errors [1]. The findings could help bring scalable, high-performance quantum computers closer to reality.
The researchers’ method involves controlling the cavity via carefully timed microwave pulses that drive tunable interactions between the transmon and specific electromagnetic modes of the cavity. This selectivity minimizes transmon-mediated errors and enables the cavity’s stored information to be manipulated both precisely and quickly.
Chakram and his colleagues applied their technique to a microwave cavity hosting ten active electromagnetic modes. They demonstrated storage and retrieval of information, as well as the creation of so-called NOON states between selected mode pairs. These highly entangled quantum states are required for quantum-limited sensing and other quantum applications. Lastly, the researchers prepared logical qubits that store information in ways that can be used to detect and correct errors.
–Ryan Wilkinson
Ryan Wilkinson is a Corresponding Editor for Physics Magazine based in Durham, UK.
References
- J. Huang et al., “Fast sideband control of a multimode cavity memory with weak dispersive coupling to a transmon,” Phys. Rev. X 16, 011058 (2026).