Fabio Sebastiano Electronic interfaces for quantum processors the - PowerPoint PPT Presentation

Fabio Sebastiano Electronic interfaces for quantum processors – the challenges

A scalable quantum computer ADC MUX ADC N-qubit Digital Quantum control Processor DAC Challenges DEMUX • Performance DAC • Power • Cryogenic T sensor References T = 20 mK – 100 mK T = 1 K - 4 K T = 300 K

Electronics at cryogenic temperature? • Operate @ 4 K, 20 mK, … • Superconducting devices (RSFQ, RQL, SQUID, JPA …) • Semiconductors Minimum temp. Si BJT 100 K Ge BJT 20 K Most used today SiGe HBT < 1 K VLSI GaAs MESFET < 4 K Very Large Scale CMOS* 30 mK or below? Integration *CMOS = Complementary Metal Oxide Semiconductor

Cryo-CMOS for scalable quantum computing Specifications ADC MUX ADC Cryo-CMOS N-qubit Digital devices Quantum control Processor DAC DEMUX Challenges DAC • Performance • Power T sensor References • Cryogenic T = 20 mK – 100 mK T = 1 K - 4 K T = 300 K

Specifications – Co-simulating cryo-CMOS and qubits Qubit simulator Circuit simulator (Hamiltonian) Electrical signals V DD R bias1 M 6 Ω Fidelity M 5 M 10 M 7 (control) C AC M 2 M 4 V B2 Fidelity M 1 M 3 (read-out)

Example – Microwave generation Electrical specifications Error Source Type Value Error [ppm] Nuclear spin noise 1.9 kHz rms 4 inaccuracy 11.2 kHz 125 Microwave frequency noise 11.2 kHz rms 125 (nominally 6 GHz) wideband noise 12 μV rms 125 Phase Inaccuracy 0.64° 125 Microwave amplitude inaccuracy 14 μV 125 (nominally 17 mV) noise 14 μV rms 125 Microwave duration inaccuracy 3.6 ps 125 (nominally 50 ns) noise 3.6 ns rms 125 + 1000 ppm (Rabi freq. 1 MHz) ⇒ Fidelity = 99.9%

Example – Microwave generation 640 MHz Q1 Q2 Q64 . . . CMOS @ room-temperature • – Digital-to-analog converter (10-bit 500 MS/s) P = 24 mW – Phase-locked loop (9.2 - 12.7 GHz) P = 13 mW P tot = 37 mW/qubit With frequency multiplexing? • – Digital-to-analog converter (12-bit 1.6 GS/s) P = 40 mW – Phase-locked loop (9.2 - 12.7 GHz) P = 13 mW P tot < 1 mW/qubit [Lin, JSSC 2012] [Raczkowski, JSSC 2015] [Lin, JSSC 2014]

Cryo-CMOS devices 40 40 40 T=300K T=300K T=300K T=20K T=20K T=4K 30 30 30 + I DS V DS + I DS [ µ A] I DS [ µ A] I DS [ µ A] NMOS NMOS NMOS V GS 20 20 20 _ _ 10 10 10 W/L=0.4/1.61 PMOS PMOS PMOS 0.322-μm CMOS V GS = 1.5 V 0 0 0 0 0 0 0.5 0.5 0.5 1 1 1 1.5 1.5 1.5 2 2 2 2.5 2.5 2.5 V DS [V] V DS [V] V DS [V]

Cryo-CMOS devices 2 2 0.8 0.8 0.16 µ m CMOS – thick oxide 40 nm CMOS – thin oxide 1.5 1.5 0.6 0.6 I D [mA] I D [mA] I D [ µ A] I D [ µ A] 1 1 0.4 0.4 0.5 0.5 0.2 0.2 0 0 0 0 0 0 0.5 0.5 1 1 1.5 1.5 2 2 2.5 2.5 3 3 3.3 3.3 0 0 0.2 0.2 0.4 0.4 0.6 0.6 0.8 0.8 1 1 1.1 1.1 V DS [V] V DS [V] V DS [V] V DS [V]

Towards a scalable quantum computer Low-noise amplifier Cryo-FPGA ADC ADC MUX MUX ADC ADC N-qubit N-qubit Digital Digital Quantum Quantum control control Processor Processor DAC DAC DEMUX DEMUX DAC DAC T sensor T sensor References References T = 20 mK – 100 mK T = 20 mK – 100 mK T = 300 K T = 300 K T = 1 K - 4 K T = 1 K - 4 K Temp. sensors RF oscillator