Building an open control stack for quantum computers using RISC-V ecosystems

Information Classification: General
CONTRIBUTE.
COLLABORATE.
COMMERCIALIZE.
December 8-10 | Virtual Event

Building an Open Control Stack for Quantum Computers
using RISC-V Ecosystem
Anastasiia Butko
Research Scientist
Lawrence Berkeley National Laboratory
#RISCVSUMMIT

Quantum Computers
Introduction

QUANTUM COMPUTER VS. ACCELERATOR

INACCURACY OF TERMINOLOGY
Quantum computer ≠ Quantum Processing Unit (QPU)

QUANTUM SYSTEM
Quantum computer ≠ Quantum Processing Unit
Quantum computer = Quantum Processing Unit + Control Hardware
User
Quantum Processing Unit
Cryogenic Control Architecture for Large-Scale Quantum Computing, J. M. Hornibrook et al., Phys. Rev. Applied 3, 024010,
(2015)

Abstraction Levels
Main concepts in quantum computing

• have been an active area of study long before any physical implementation of
quantum computers became available
• recent research and development bring the awareness of hardware to the high levels
(NISQ applications), but abstraction and modularity is crucial for scalability
ABSTRACTION LEVELS
Awareness across the Stack

• have been an active area of study long before any physical implementation of
quantum computers became available
• recent research and development bring the awareness of hardware to the high levels
(NISQ applications), but abstraction and modularity is crucial for scalability
ABSTRACTION LEVELS
• operate at the level of physical pulses with very limited or no notion about software

ABSTRACTION LEVELS
• Bridging the gap in between the theory and practice

System Architecture
How is it done today and why it is NOT going to work in the future

CONTROL UNIT
Software vs. Hardware Implementation
Software Control
• Everything in one place
• Easier to implement and modify
• NISQ experiments
• Long latency
• Limited bandwidth
• Limited flexibility (bit granularity)
• Poor scalability
S e q u e n c e
B a n d w i d t h
L a t e n c y 1 L a t e n c y 2
M E M
✅
✅
✅
❌
❌
❌
❌
L O A D

Q A S M
L a t e n c y 1 L a t e n c y 2
M E M
Hardware Control
• Reduced latency
• Fast feedback
• Extended functionality in-place
• Potential scalability
• Separation of concepts
• Beyond-NISQ
• Requires specialized solution
• Harder to implement and modify
• Requires commercial support
❌
❌
✅
✅
✅
✅
✅
✅
CONTROL UNIT
Software vs. Hardware Implementation
❌

• Quantum Instruction Set Architecture (QUASAR)
• extension to RISC-V ISA (open-source, modular, active community, eco-system)
• supports quantum operations, timing control, etc.
• transparent, adaptable, open
• New tools in hardware design and evaluation
• high-level HDL (Chisel)
• modular and parametrizable modules
Requires specialized solution
Harder to implement and modify
HARDWARE APPROACH
Building an efficient software-hardware interface
✅
✅

RISC-V for Quantum
How we build and evaluate quantum control stack using RISC-V eco-system

QUASAR Extensions
Different approaches
• Greenfield extension approach
• Tightly integrated with the processor micro-architecture
• High-level of customization
• May cause conflicts with other extensions
• Requires compiler extension
• RoCC co-processor adaptation
• Existing software support
• Modular approach easily interactable into a big system
• Lower-level of customization and flexibility
P r o c e s s o r
C o r e
L 1 I L 1 D
R I S C - V R o c k e t R o C C
m r q
m r s
c m d
r e s p
b u s y
Q U A S A R
D E C
W B
M E M
Q I
T S R
M S R
Q
P
U

QUASAR Extensions
Different approaches
• Greenfield extension approach
• Tightly integrated with the processor micro-architecture
• High-level of customization
• May cause conflicts with other extensions
• Requires compiler extension
• RoCC co-processor adaptation
• Existing software support
• Modular approach easily interactable into a big system
• Lower-level of customization and flexibility
P r o c e s s o r
C o r e
L 1 I L 1 D
R I S C - V R o c k e t R o C C
m r q
m r s
c m d
r e s p
b u s y
Q U A S A R
D E C
W B
M E M
Q I
T S R
M S R
Q
P
U
• Quantum ISA Spec evaluation
• Metrics and methodology
• Comparison against existing solutions
• Scalability and performance projections
Understanding Quantum Control Processor Capabilities and Limitations through Circuit
Characterization, A. BUTKO et al., IEEE International Conference on Rebooting Computing
(ICRC), December 2020
https://arxiv.org/abs/1909.11719

System Architecture Implementation
From core to system architecture
• Using Freedom Platform (SiFive) for system integration on VC707 FPGA

• Run Linux
• Remote communication
• Periphery support
• Security

• RoCC Interface
• Pulse Library Table (PLT)
• Additional functionalities
(loading Waveform Memory
for calibration, readout post-
processing )

• Analog backend
• Phase manipulation
• Fast readout
• Timing control

High-level circuit
QUASAR library
Linux OS
int main() {
qReset(); //reset hardware resources to ZERO
x90i(1); //apply the X90 immediate gate on qubit 1
tsi(5); //advances the time stamp on 5 cycles
y90i(0); //apply the Y90 immediate gate on qubit 0
return 0;
}
#define XCUSTOM_ACC 0
#define q_DO_X90 1
#define x90i(qid)
ROCC_INSTRUCTION_0_R_R(XCUSTOM_ACC, qid, 0, q_DO_X90);
Software Stack
From high-level circuit description to Linux executable
Control Pulses generated by
the Analog Backend

FUTURE WORK
• How scalable are our approaches?
• QUASAR supports up to 512 qubits
• Quantum vector extension (qV) to express single-instruction multiple-qubits multiple-gates parallelism
• Multiple QUASAR co-processors, multiple FPGAs
• Bit manipulation for error-correction code
• Cool technologies
• Cryo-CMOS: energy dissipation, noise
• Superconducting: how the micro-architecture will change?
… and much more

Advanced Quantum Testbed @ LBNL
Superconducting Quantum Processors at the Entanglement Frontier
1 mW Dilution fridge Cold stage
Commercial
Control
LBNL/ATAP
Control
3D Integrated Quantum Processor
Units (QPU)
Team: LBNL, UC Berkeley,
Bleximo, MIT-LL

Thank you for joining us.
Contribute to the RISC-V conversation on social!
#RISCVSUMMIT @risc_v

Building an open control stack for quantum computers using RISC-V ecosystems

Recommended

Recommended

More Related Content

What's hot

What's hot (20)

Similar to Building an open control stack for quantum computers using RISC-V ecosystems

Similar to Building an open control stack for quantum computers using RISC-V ecosystems (20)

More from RISC-V International

More from RISC-V International (20)

Recently uploaded

Recently uploaded (20)

Building an open control stack for quantum computers using RISC-V ecosystems