A Scalable Cryo-CMOS 2-to-20GHz Digitally Intensive Controller for 4×32 Frequency Multiplexed Spin in Qubits/Transmons in 22nm FinFET Technology for Quantum Computers
van Dijk, J.P.G.
Quantum computers (QC), comprising qubits and a classical controller, can provide exponential speed-up in solving certain problems. Among solid-state qubits, transmons and spin-qubits are the most promising, operating ≪ 1K. A qubit can be implemented in a physical system with two distinct energy levels representing the |0⟩ and |1⟩ states, e.g. the up and down spin states of an electron. The qubit states can be manipulated with microwave pulses, whose frequency f matches the energy level spacing E = hf (Fig. 19.1.1). For transmons, f ∼6GHz, for spin qubits f ∼20GHz, with the desire to lower it in the future. Qubit operations can be represented as rotations in the Bloch sphere. The rotation axis is set by the phase of the microwave signal relative to the qubit phase, which must be tracked for coherent operations. The pulse amplitude and duration determine the rotation angle. A π-rotation is typically obtained using a 50ns Gaussian pulse for transmons and a 500ns rectangular pulse for spin qubits with powers of -60dBm and -45dBm, respectively.
CMOS integrated circuits
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Electron energy levels
Energy level spacings
Solid state qubits
High Tech Systems & Materials
Institute of Electrical and Electronics Engineers IEEE
IEEE International Solid-State Circuits Conference, ISSCC 2020, 16-20 February 2020, 304-306