Special Session: Quantum Carry Lookahead Adders for NISQ and Quantum Image Processing

Himanshu Thapliyal, Edgard Munoz-Coreas, Vladislav Khalus

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

3 Citations (SciVal)


Progress in quantum hardware design is progressing toward machines of sufficient size to begin realizing quantum algorithms in disciplines such as encryption and physics. Quantum circuits for addition are crucial to realize many quantum algorithms on these machines. Ideally, quantum circuits based on fault-tolerant gates and error-correcting codes should be used as they tolerant environmental noise. However, current machines called Noisy Intermediate Scale Quantum (NISQ) machines cannot support the overhead associated with fault-tolerant design. In response, low depth circuits such as quantum carry lookahead adders (QCLA)s have caught the attention of researchers. The risk for noise errors and decoherence increase as the number of gate layers (or depth) in the circuit increases. This work presents an out-of-place QCLA based on Clifford+T gates. The QCLAs optimized for T gate count and make use of a novel uncomputation gate to save T gates. We base our QCLAs on Clifford+T gates because they can eventually be made fault-tolerant with error-correcting codes once quantum hardware that can support fault-tolerant designs becomes available. We focus on T gate cost as the T gate is significantly more costly to make fault-tolerant than the other Clifford+T gates. The proposed QCLAs are compared and shown to be superior to existing works in terms of T-count and therefore the total number of quantum gates. Finally, we illustrate the application of the proposed QCLAs in quantum image processing by presenting quantum circuits for bilinear interpolation.

Original languageEnglish
Title of host publicationProceedings - 2020 IEEE 38th International Conference on Computer Design, ICCD 2020
Number of pages4
ISBN (Electronic)9781728197104
StatePublished - Oct 2020
Event38th IEEE International Conference on Computer Design, ICCD 2020 - Hartford, United States
Duration: Oct 18 2020Oct 21 2020

Publication series

NameProceedings - IEEE International Conference on Computer Design: VLSI in Computers and Processors
ISSN (Print)1063-6404


Conference38th IEEE International Conference on Computer Design, ICCD 2020
Country/TerritoryUnited States

Bibliographical note

Publisher Copyright:
© 2020 IEEE.


  • Noisy Intermediate Scale Quantum
  • Quantum Arithmetic
  • Quantum Circuits
  • Quantum Computing
  • Quantum Image Processing
  • uncomputation gate

ASJC Scopus subject areas

  • Hardware and Architecture
  • Electrical and Electronic Engineering


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