Quantum simulators hold promise for solving many intractable problems. However, a major challenge in quantum simulation, and quantum computation in general, is to solve problems withlimited physical hardware. Currently, this challenge is tackled by designing dedicated devices for specific models, thereby allowing to reduce control requirements and simplify the construction. Here, we suggest a new method for quantum simulation in circuit QED, that provides versatility in model design and complete control over its parameters with minimal hardware requirements. We show how these features manifest through examples of quantum simulation of Dirac dynamics, which is relevant to the study of both high-energy physics and 2D materials. We conclude by discussing the advantages and limitations of the proposed method.
High power measurement-induced cavity response is investigated in the |g>, |e>, and |f> states of a transmon. All the states exhibit photon blockades above a certain critical value,a phenomenon that has previously been understood based on the bistability of semiclassical Duffing oscillators. The measurement-induced state transition (MIST) to high-level transmon states is expected to be one contributor to the bistability; however, the critical values measured in the |e> and |f> states are not coincident with the MIST. To understand this discrepancy, we utilize the recently developed semiclassical dynamics model of a cavity photon state. The appearance of dim and bright cavity states obtained from the model’s steady-state solution leads to the photon blockades at lower critical photon numbers, and this can explain the response of the bistable region in the |e> and |f> states.
We present a systematic study of the effects of shielding on the internal quality factors (Qi) of Al and TiN microwave resonators designed for use in quantum coherent circuits. Measurementswere performed in an adiabatic demagnetization refrigerator, where typical magnetic fields of 200 {\mu}T are present at the unshielded sample stage. Radiation shielding consisted of 100 mK and 500 mK Cu cans coated with infrared absorbing epoxy. Magnetic shields consisted of Cryoperm 10 and Sn plating of the Cu cans. A 2.7 K radiation can and coaxial thermalization filters were present in all measurements. TiN samples with Qi = 1.3∗106 at 100 mK exhibited no significant variation in quality factor when tested with limited shielding. In contrast, Al resonators showed improved Qi with successive shielding, with the largest gains obtained from the addition of the first radiation and magnetic shields and saturating before the addition of Sn plating infrared absorbing epoxy.