# Superconducting Qubit Arrays for Quantum Logic Circuits

**Apr 15, 2016 at 11:00 AM - 1:00 PM**

202/204 Physics

Quantum computing holds the promise of exploiting superposition and entanglement to surpass conventional digital logic in certain classes of problems. Superconducting qubit circuits at millikelvin temperatures have recently demonstrated key advances such as robust and simple multi-qubit gates, the integration of superconducting qubits into arrays of four or more, and gate fidelities reaching 99%. [1,2,3] The technology has thus matured to the point of integrating multiple qubits to form functional quantum logic circuits. Such circuits will enable quantum error correction via the ‘surface code’ or similar algorithms. In this talk I will discuss a multi-qubit architecture under development at IBM Research, in which two-dimensional arrays of fixed-frequency transmon qubits are coupled via microwave-waveguide buses and microwave-driven two-qubit gates. To scale this architecture into a fully fault-tolerant quantum logic circuit will require advances in the basic physics, engineering and operation of these devices. [4] I will survey these challenges and focus in particular on two issues: 1) how to precisely allocate qubit frequencies in the vicinity of 5 GHz; and 2) how to rapidly read out the qubit state while minimizing losses via the Purcell effect. [5]

**References**

[1] J. M. Chow et al, Nature Communications 5, 4015 (2014).

[2] A. D. Corcoles et al, Nature Communications 6, 6979 (2015), 10.1038/ncomms7979.

[3] S. Sheldon et al, arXiv:1603.04821v1 [quant-ph].

[4] J. M. Gambetta et al, arXiv:1510.04375v1 [quant-ph].

[5] N. T. Bronn et al, Appl Phys Lett 107, 172601 (2015).

**Jared Hertzberg** IBM

Host: Matt LaHaye | Contact: Yudaisy Salomon Sargenton, yssargen@syr.edu