&Bullet; physics 14, p45
A detector made from superconducting qubits could enable researchers to search for dark matter particles 1,000 times faster than other techniques.
It is believed that dark matter particles such as axions and hidden photons occasionally “light up” and transform into ordinary photons. This process may enable researchers to spot the otherwise invisible particles. Now, Akash Dixit of the University of Chicago and colleagues propose and demonstrate a way to perform these recognitions with qubits  . Their calculations show that their technology is much more sensitive to the detection of photons converted from hidden photons than conventional approaches.
In the new method, a superconducting qubit searches for photons in a microwave cavity. The qubit can act as a detector because the energy required to excite the photon – something researchers can monitor – depends on the number of photons in the cavity.
For every photon that appears, a conventional microwave cavity detector would measure its position and momentum and introduce a significant level of noise due to the uncertainty principle. Dixit and colleagues’ qubit-based method only needs to measure one observable element – the number of photons in the cavity – which reduces the noise problem. In addition, the qubit method leaves the photon intact and allows repeated measurements that reduce the likelihood of false detection. These advantages could make the search for dark matter about 1000 times faster than traditional microwave cavity approaches.
To demonstrate the technology, Dixit and colleagues have already excluded new areas of the parameter space for dark matter from hidden photons. They say that with some modifications, the method could also be used to find axions. For example, the device would have to work in a magnetic field that is required to convert incoming axions into photons.
–Erika K. Carlson
Erika K. Carlson is Corresponding Editor for physics based in New York City.
- AV Dixit et al., “Searching for dark matter with a superconducting qubit” Phys. Rev. Lett.126141302 (2021).