Systems and techniques that facilitate controlling TLS via on-chip filtering to prevent qubit energy loss are provided. In various embodiments, a system can comprise a quantum device including a qubit device on a substate. In various embodiments, the quantum device can include an electrode placed in proximity to the qubit device. In various embodiments, an electrical filter can be connected to the electrode. In various embodiments, the quantum device can comprise a voltage source that can be connected to the electrode via the electrical filter. In various embodiments, the voltage source can control a voltage to the electrode to shift a resonant frequency of one or more defects to reduce two level system (TLS) impact on the qubit device.

Described herein relates to an antenna-coupled graphene Josephson-junction THz/mm-wave apparatus (hereinafter video) detector apparatus and methods thereof. Highly sensitive, broadly tunable detectors may be needed for future sensing applications and quantum information systems. In an embodiment, the video detector apparatus may comprise stacked graphene sheets having a magic twist angle between their in-plane symmetry axes. As such, the material may display superconductivity with at least 2 K transition temperature. Additionally, the video detector apparatus may depend on the decrease in the maximum zero-voltage DC current when AC current is driven through the junction.

Electrical communication between a sample (such as a quantum chip, semiconductor sample etc.) in a low temperature environment and an external device is affected via signal lines printed on rigid printed circuit board (PCB) located within a region of the low temperature environment (e.g., a non-uniform magnetic field region). One example application is performing a measurement of an electrical property of the sample at a low signal frequency with a short measurement integration time, although the subject matter is not limited in this respect. Another application is routing an electrical control signal to the sample.

Methods for fabricating optically active quantum memories into quantum-grade diamond thin films and then bonding them to semiconductor substrates are described. Semiconductor substrates are optically and electronically functionalized in preparation for using a flip-chip bonding technique to bond the functionalized substrates to overgrown diamond thin films that host color centers. By purposefully growing quantum-grade diamond thin films and implanting them with color centers separately from fabrication processes that functionalize the substrates, the high quality, purity, and crystallinity of the thin films are preserved, while also allowing for further customization of the types of color centers that are implanted into the diamond.

A transistor comprises a planar layer of a topological material located between a gate electrode and a dielectric layer. The topological material exhibits a topological phase transition between a trivial state and a non-trivial state at a critical electric field strength on application of an electric field in a direction perpendicular to the planar layer. The topological material exhibits a change in bandgap, in the presence of the electric field, having a Rashba spin-dependent bandgap contribution that is at least three times as large as a non-spin-dependent bandgap contribution.