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Cited by 151Quantum Computing Algorithms and ArchitectureQuantum Information and CryptographyQuantum Mechanics and Applications

The DOI matches its Crossref record; 34 of the 34 references it cites were found in a registry or an index.

Circuit-Based Quantum Random Access Memory for Classical Data

Open access
Park, Daniel K., Petruccione, Francesco, Rhee, June-Koo Kevin·2019·Scientific Reports
DOI 10.1038/s41598-019-40439-3PMC PMC6408577
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Abstract

A prerequisite for many quantum information processing tasks to truly surpass classical approaches is an efficient procedure to encode classical data in quantum superposition states. In this work, we present a circuit-based flip-flop quantum random access memory to construct a quantum database of classical information in a systematic and flexible way. For registering or updating classical data consisting of M entries, each represented by n bits, the method requires O(n) qubits and O(Mn) steps. With post-selection at an additional cost, our method can also store continuous data as probability amplitudes. As an example, we present a procedure to convert classical training data for a quantum supervised learning algorithm to a quantum state. Further improvements can be achieved by reducing the number of state preparation queries with the introduction of quantum forking.

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Figures

Figure 1 Quantum circuit for FF-QRAM that writes bit strings (d→)^(l) and (d→)^(l+1) as a quantum superposition state with probability amplitudes using multi-qubit controlled rotation gates determined by θ(l) and θ(l+1), respectively. The double lines indicate classically controlled operations, and the empty (filled) circle indicates that the gate is activated when the control bit (qubit) is 0 (1). The dotted and numbered arrows indicate the various steps described in the main text.
Figure 1 Quantum circuit for FF-QRAM that writes bit strings (d→)^(l) and (d→)^(l+1) as a quantum superposition state with probability amplitudes using multi-qubit controlled rotation gates determined by θ(l) and θ(l+1), respectively. The double lines indicate classically controlled operations, and the empty (filled) circle indicates that the gate is activated when the control bit (qubit) is 0 (1). The dotted and numbered arrows indicate the various steps described in the main text.CC BY · PubMed Central
Figure 2 Error rate at each time step required for writing M classical data and n=log2(M) with the success probability ps. Solid lines with filled symbols are obtained when CnRp(θ) can fail at any of its decomposed locations independently, while dashed lines with open symbols are obtained when the multi-qubit controlled rotation only causes independent errors on n + 1 qubit, as described in the main text.
Figure 2 Error rate at each time step required for writing M classical data and n=log2(M) with the success probability ps. Solid lines with filled symbols are obtained when CnRp(θ) can fail at any of its decomposed locations independently, while dashed lines with open symbols are obtained when the multi-qubit controlled rotation only causes independent errors on n + 1 qubit, as described in the main text.CC BY · PubMed Central
Figure 3 Quantum circuit for preparing the QDB for a quantum support vector machine. The gates are shown for writing an ith training data only. The gates shaded in gray are added solely for illustrating the flip-flop process, and are not implemented in practice.
Figure 3 Quantum circuit for preparing the QDB for a quantum support vector machine. The gates are shown for writing an ith training data only. The gates shaded in gray are added solely for illustrating the flip-flop process, and are not implemented in practice.CC BY · PubMed Central
Figure 4 (a) Quantum forking to reduce the number of QRAM calls for evaluating the functions of inner products. The swap operation is represented by two × symbols connected with a vertical line. (b) Quantum forking circuit for evolving the target state |Φ〉 under three different unitary operations in each branch (subspace). Thicker horizontal lines indicate multi-qubit channels, |a〉 is an arbitrary ancilla state, and H (H3) represents the Hadamard gate on a qubit (qutrit).
Figure 4 (a) Quantum forking to reduce the number of QRAM calls for evaluating the functions of inner products. The swap operation is represented by two × symbols connected with a vertical line. (b) Quantum forking circuit for evolving the target state |Φ〉 under three different unitary operations in each branch (subspace). Thicker horizontal lines indicate multi-qubit channels, |a〉 is an arbitrary ancilla state, and H (H3) represents the Hadamard gate on a qubit (qutrit).CC BY · PubMed Central
Figure 5 Quantum circuit for implementing a C4NOT gate using 5 Toffoli gates and 2 ancilla qubits prepared in |0〉 in 3 steps. The control bits are a, b, c and d, and the target qubit is |t〉. The gates after the Toffoli gate for conditionally flipping the target qubit uncompute the ancila qubits in order to unentangle the ancillae from the system.
Figure 5 Quantum circuit for implementing a C4NOT gate using 5 Toffoli gates and 2 ancilla qubits prepared in |0〉 in 3 steps. The control bits are a, b, c and d, and the target qubit is |t〉. The gates after the Toffoli gate for conditionally flipping the target qubit uncompute the ancila qubits in order to unentangle the ancillae from the system.CC BY · PubMed Central

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Research works printed but not linked: 1

  1. Park, D. K., Sinayskiy, I., Fingerhuth, M., Petruccione, F. & Rhee, J. K. Quantum forking for fast weighted power summation. arXiv:1902.07959 [quant-ph] (2019). · arXiv

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Metadata

Authors
Park, D. K., Petruccione, F., & Rhee, J.-K. K.
Affiliations
Korea Advanced Institute of Science and Technology (KR)
Corresponding author
Rhee, June-Koo Kevin
ORCID
Venue
Scientific Reports
Publisher
Springer Science and Business Media LLC
Published
2019-03-08
Volume
9
Issue
1
Pages
3949-3949
ISSN
2045-2322 (ISSN-L)
DOI
10.1038/s41598-019-40439-3
PMC
PMC6408577
OpenAlex
W2909846583
Cited by
151
References
34
Citations by year
2026: 11 · 2025: 28 · 2024: 22 · 2023: 22 · 2022: 26 · 2021: 24 · 2020: 15 · 2019: 3
FWCI
7.76
Type
journal article
Language
en
Open access
Licence
Locations
  • Scientific Reports (publishedVersion, cc-by)
  • Europe PMC (PubMed Central) (publishedVersion, cc-by)
  • PubMed Central (publishedVersion, cc-by)
  • PubMed (publishedVersion)
  • arXiv (Cornell University) (submittedVersion)
  • DOAJ (DOAJ: Directory of Open Access Journals) (submittedVersion)
  • arXiv (Cornell University)
Funders
  • National Research Foundation (2016R1A5A1008184)
  • National Research Foundation of Korea (2016R1A5A1008184)
  • Korea Advanced Institute of Science and Technology (2016R1A5A1008184)
  • Iran Telecommunication Research Center
  • Ministry of Science and ICT, South Korea (IITP-2018, 2016R1A5A1008184)
  • Institute for Information and Communications Technology Promotion (IITP-2018-2015-0-00385, IITP-2018-2018-0-01402)
Topics
  • Physical Sciences › Computer Science › Artificial Intelligence › Quantum Computing Algorithms and Architecture
  • Physical Sciences › Physics and Astronomy › Atomic and Molecular Physics, and Optics › Quantum Information and Cryptography
  • Physical Sciences › Physics and Astronomy › Atomic and Molecular Physics, and Optics › Quantum Mechanics and Applications
Keywords
quantum random access memory, flip-flops, quantum superposition, post-selection

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