the qick (quantum instrumentation control kit): readout

The QICK (Quantum Instrumentation Control Kit): Readout and control for qubits and detectors

L. Stefanazzi et al., arXiv:2110.00557v1 (2021)

Niyaz Beysengulov

Qubit measurements in circuit QED

Transmon qubit coupled to a 1D transmission-line resonator

QND measurement

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HBMi = d ·E+�p

dipole moment of the transmon

resonator’s zero-point electric field

d

dispersive regime:

Jaynes-Cummings Hamiltonian:

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�e,g = ±�`+i�M⇣2�

⌘

A. Blais et al., Review of Modern Physics 93 (2021)

Qubit measurements in circuit QED

The microwave measurement chain

Signal at the output of cavity (including all amplifier chain):

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�e,g = ±�`+i�M⇣2�

⌘

Local Oscillator:

IQ mixer output:

homodyne detection

heterodyne detection

I

QA. Blais et al., Review of Modern Physics 93 (2021)

Digital demodulation and filtering

Y. Salathé et al., Physical Review Applied 9.3 (2018): 034011.

Heterodyne detection scheme (using FPGA)

Digital demodulation and filtering

Voltage signal at the ADC input:

ADC sample rate:

IF frequency:

ADC resolution:±1 V range and 14 bit: discretisation step 2-13 V ≈ 0.12 mV

1. Digitisation

Y. Salathé et al., Physical Review Applied 9.3 (2018): 034011.

Heterodyne detection scheme (using FPGA)

Digital demodulation and filtering

2. Digital mixing

sideband at zero frequency

Heterodyne detection scheme (using FPGA)

Digital demodulation and filtering

3. Digital low-pass filter

moving average

4. State discrimination

Y. Salathé et al., Physical Review Applied 9.3 (2018): 034011.

Heterodyne detection scheme (using FPGA)

Quantum Instrumentation Control Kit

New FPGA platform

• high speed DAC • high speed ADC • programmable FPGA logic • conventional microprocessor

L Stefanazzi et al., arXiv:2110.00557v1 (2021)

Quantum Instrumentation Control Kit

MotherboardXilinx ZCU111 RFSoC evaluation board

• eight 6.5 Gs/s DACs • eight 4 GS/s ADCs

XCZU28DR RFSoC chip

Includes: - configurable IQ digital up/down conversion - integrated num.controlled oscillator - gain matrix - digital filters

direct synthesize carrier frequencies up to 3 GHz in first Nyquist zone and up to 6 GHZ in the second Nyquist zone mode

Quantum Instrumentation Control Kit

Analog front-endQICK RF board

More than 200 components: amplifiers, mixers, filters, local oscillator generators, switches, drivers

Eight RF or DC coupled outputs

Quantum Instrumentation Control Kit

Analog front-endQICK RF board

More than 200 components: amplifiers, mixers, filters, local oscillator generators, switches, drivers

Eight RF or DC (1.5 GHz bandwidth) coupled inputs

System architecture and functionality

QICK firmware block diagram

tProcessor custom processor

with timed instructions

Processing System Programmable Logic

Signal generators pulses with complex envelopes

which modulates a high-speed carrier

ZYNQ system system with own DDR4 memory,

running LINUX OS on a multi-core ARM processor

Readout block fast digital downconversion

QICK RF board Performance

Spectrum of mixer upconversion Latencies

Characterization of a transmon qubit

https://github.com/openquantumhardware/qick