Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

arXiv:quant-ph/0410029 · Physical Review A

Quantum memory for superconducting qubits

Emily Pritchett, Michael R. Geller

Published Jul 14, 2005• 19 citations
arXivHTMLPDF

Abstract

Many protocols for quantum computation require a memory element to store qubits. We discuss the speed and accuracy with which quantum states prepared in a superconducting qubit can be stored in and later retrieved from an attached high-$Q$ resonator. The memory fidelity depends on both the qubit-resonator coupling strength and the location of the state on the Bloch sphere. Our results show that a quantum memory demonstration should be possible with existing superconducting qubit designs, which would be an important milestone in solid-state quantum information processing. Although we specifically focus on a large-area, current-biased Josesphson-junction phase qubit coupled to the dilatational mode of a piezoelectric nanoelectromechanical disk resonator, many of our results will apply to other qubit-oscillator models.

DOI
10.1103/physreva.72.010301

Related papers

Superconducting qubits coupled to nanoelectromechanical resonators: An architecture for solid-state quantum-information processing

Michael R. Geller, Andrew N. Cleland

We describe the design for a scalable, solid-state quantum-information-processing architecture based on the integration of GHz-frequency nanomechanical resonators with Josephson tunnel junctions, which has the potential for demonstrating a variety of single- and multiqubit operations critical to quantum computation. The computational qubits are eigenstates of large-area, current-biased Josephson junctions, manipulated and measured using strobed external circuitry. Two or more of these phase qubits are capacitively coupled to a high-quality-factor piezoelectric nanoelectromechanical disk resonator, which forms the backbone of our architecture, and which enables coherent coupling of the qubits. The integrated system is analogous to one or more few-level atoms (the Josephson junction qubits) in an electromagnetic cavity (the nanomechanical resonator). However, unlike existing approaches using atoms in electromagnetic cavities, here we can individually tune the level spacing of the ``atoms'' and control their ``electromagnetic'' interaction strength. We show theoretically that quantum states prepared in a Josephson junction can be passed to the nanomechanical resonator and stored there, and then can be passed back to the original junction or transferred to another with high fidelity. The resonator can also be used to produce maximally entangled Bell states between a pair of Josephson junctions. Many such junction-resonator complexes can be assembled in a hub-and-spoke layout, resulting in a large-scale quantum circuit. Our proposed architecture combines desirable features of both solid-state and cavity quantum electrodynamics approaches, and could make quantum-information processing possible in a scalable, solid-state environment.

arXiv:quant-ph/0409179•Physical Review A•Mar 14, 2005•85 citations

Proposal for quantum memory miniaturization in superconducting circuit QED

Genting Dai, Kaiyong He, Yongcheng He +3 more

Superconducting circuit quantum electrodynamics is the main architecture for implementation of quantum processors. This work presents a proposal to miniaturize quantum memory devices by combining the quantum memory qubits encoded directly in the first two Fock states ${|0\ensuremath{\rangle},|1\ensuremath{\rangle}}$ and the bus channel in the same specially designed multimode cavity. One key feature of the resonant modes used for quantum memory is that the microwave current is localized, which facilitates the storage and retrieval of information in superconducting qubits while preventing crosstalk from other resonant modes. Frequency design and distinct coupling strengths in this kind of device are analyzed with electromagnetic simulations and numerical calculations. The quantum memory properties, e.g., storage speed, fidelity, and stability, are examined in four cases: (1) memory operation of single-qubit state, (2) disturbing effects, (3) coupling operation, and (4) entangled states storage. Decoherence time of the quantum processor can be extended to more than one order of magnitude longer than that without the memory. By integrating transmons with optimally designed coplanar waveguide multimode quantum memories, the present study could provide an optimistic perspective for the development of large-scale superconducting quantum processors.

Physical Review A•Apr 24, 2023•1 citation

Scheme for realizing quantum-information storage and retrieval from quantum memory based on nitrogen-vacancy centers

Yu-Jing Zhao, Xi-Ming Fang, Fang Zhou +1 more

We demonstrate a scheme for realizing quantum-information storage (retrieval) into (from) a quantum memory using a hybrid quantum system, which consists of $N$ nitrogen-vacancy (N-$V$) centers (as memory), $N$ transmission line resonators (TLRs) (as data bus), and $N$ current-biased Josephson-junction (CBJJ) superconducting phase qubits (as heads of read and write). By virtually exciting the vibrational modes of the TLRs, this can produce an effective coupling between the N-$V$ centers and the CBJJs in the system. Because the operation time ($\ensuremath{\sim}{10}^{\ensuremath{-}8}$ s) is much shorter than the decoherence time of the CBJJ ($\ensuremath{\sim}{10}^{\ensuremath{-}5}$ s), the quantum information can be transferred between the N-$V$ centers and the CBJJs easily. Owing to the strong-coupling condition $[\ensuremath{\lambda}/2\ensuremath{\pi}\ensuremath{\gg}({\ensuremath{\gamma}}_{eg},\ensuremath{\Gamma},{\ensuremath{\gamma}}_{\ensuremath{\phi}})]$ and the long coherence time ($\ensuremath{\sim}{10}^{\ensuremath{-}3}$ s) of the N-$V$ centers, the quantum information can be stored in the memory steadily, and it can be retrieved with a high fidelity ($>96%$). This scheme provides a scalable way of exchanging quantum information between different quantum interfaces, and has the experimental feasibility with currently available experimental technology.

Physical Review A•Nov 26, 2012•18 citations

Hybrid Quantum Circuit with a Superconducting Qubit Coupled to a Spin Ensemble

Yuimaru Kubo, Cécile Grèzes, Andreas Dewes +15 more

We report the experimental realization of a hybrid quantum circuit combining a superconducting qubit and an ensemble of electronic spins. The qubit, of the transmon type, is coherently coupled to the spin ensemble consisting of nitrogen-vacancy centers in a diamond crystal via a frequency-tunable superconducting resonator acting as a quantum bus. Using this circuit, we prepare a superposition of the qubit states that we store into collective excitations of the spin ensemble and retrieve back into the qubit later on. These results constitute a proof of concept of spin-ensemble based quantum memory for superconducting qubits.

arXiv:1110.2978•Physical Review Letters•Nov 21, 2011•404 citations

Z2quantum memory implemented on circuit quantum electrodynamics

Thi Ha Kyaw, Simone Felicetti, Guillermo Romero +2 more

We present a technique to store and retrieve single- and two-qubit states into a parity-protected quantum memory implemented on a state-of-the-art superconducting circuit architecture. Our proposal relies upon a specific superconducting circuit design that permits a tunable qubit-resonator coupling strength. The latter allows us to adiabatically tune from the weak coupling to the ultrastrong coupling regime of light-matter interaction, where a controllable and well-protected effective two-level system is defined due to the Z2 parity symmetry. Storage and retrieval time of the qubit are in a few nanoseconds timescale, which is far below the effective qubit coherence time.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE•Oct 8, 2014•4 citations

Towards Realizing a Quantum Memory for a Superconducting Qubit: Storage and Retrieval of Quantum States

Shiro Saito, Xiaobo Zhu, Robert Amsüss +7 more

We have built a hybrid system composed of a superconducting flux qubit (the processor) and an ensemble of nitrogen-vacancy centers in diamond (the memory) that can be directly coupled to one another, and demonstrated how information can be transferred from the flux qubit to the memory, stored, and subsequently retrieved. We have established the coherence properties of the memory and succeeded in creating an entangled state between the processor and memory, demonstrating how the entangled state's coherence is preserved. Our results are a significant step towards using an electron spin ensemble as a quantum memory for superconducting qubits.

arXiv:1308.5130•Physical Review Letters•Sep 5, 2013•112 citations
Many protocols for quantum computation require a memory element to store qubits. We discuss the speed and accuracy with which quantum states prepared in a superconducting qubit can be stored in and later retrieved from an attached high-QQQ resonator. The memory fidelity depends on both the qubit-resonator coupling strength and the location of the state on the Bloch sphere. Our results show that a quantum memory demonstration should be possible with existing superconducting qubit designs, which would be an important milestone in solid-state quantum information processing. Although we specifically focus on a large-area, current-biased Josesphson-junction phase qubit coupled to the dilatational mode of a piezoelectric nanoelectromechanical disk resonator, many of our results will apply to other qubit-oscillator models.
We describe the design for a scalable, solid-state quantum-information-processing architecture based on the integration of GHz-frequency nanomechanical resonators with Josephson tunnel junctions, which has the potential for demonstrating a variety of single- and multiqubit operations critical to quantum computation. The computational qubits are eigenstates of large-area, current-biased Josephson junctions, manipulated and measured using strobed external circuitry. Two or more of these phase qubits are capacitively coupled to a high-quality-factor piezoelectric nanoelectromechanical disk resonator, which forms the backbone of our architecture, and which enables coherent coupling of the qubits. The integrated system is analogous to one or more few-level atoms (the Josephson junction qubits) in an electromagnetic cavity (the nanomechanical resonator). However, unlike existing approaches using atoms in electromagnetic cavities, here we can individually tune the level spacing of the ``atoms'' and control their ``electromagnetic'' interaction strength. We show theoretically that quantum states prepared in a Josephson junction can be passed to the nanomechanical resonator and stored there, and then can be passed back to the original junction or transferred to another with high fidelity. The resonator can also be used to produce maximally entangled Bell states between a pair of Josephson junctions. Many such junction-resonator complexes can be assembled in a hub-and-spoke layout, resulting in a large-scale quantum circuit. Our proposed architecture combines desirable features of both solid-state and cavity quantum electrodynamics approaches, and could make quantum-information processing possible in a scalable, solid-state environment.
Superconducting circuit quantum electrodynamics is the main architecture for implementation of quantum processors. This work presents a proposal to miniaturize quantum memory devices by combining the quantum memory qubits encoded directly in the first two Fock states ${|0\ensuremath{\rangle},|1\ensuremath{\rangle}}$ and the bus channel in the same specially designed multimode cavity. One key feature of the resonant modes used for quantum memory is that the microwave current is localized, which facilitates the storage and retrieval of information in superconducting qubits while preventing crosstalk from other resonant modes. Frequency design and distinct coupling strengths in this kind of device are analyzed with electromagnetic simulations and numerical calculations. The quantum memory properties, e.g., storage speed, fidelity, and stability, are examined in four cases: (1) memory operation of single-qubit state, (2) disturbing effects, (3) coupling operation, and (4) entangled states storage. Decoherence time of the quantum processor can be extended to more than one order of magnitude longer than that without the memory. By integrating transmons with optimally designed coplanar waveguide multimode quantum memories, the present study could provide an optimistic perspective for the development of large-scale superconducting quantum processors.
We demonstrate a scheme for realizing quantum-information storage (retrieval) into (from) a quantum memory using a hybrid quantum system, which consists of NNN nitrogen-vacancy (N-VVV) centers (as memory), NNN transmission line resonators (TLRs) (as data bus), and NNN current-biased Josephson-junction (CBJJ) superconducting phase qubits (as heads of read and write). By virtually exciting the vibrational modes of the TLRs, this can produce an effective coupling between the N-VVV centers and the CBJJs in the system. Because the operation time ($\ensuremath{\sim}{10}^{\ensuremath{-}8}$ s) is much shorter than the decoherence time of the CBJJ ($\ensuremath{\sim}{10}^{\ensuremath{-}5}$ s), the quantum information can be transferred between the N-VVV centers and the CBJJs easily. Owing to the strong-coupling condition $[\ensuremath{\lambda}/2\ensuremath{\pi}\ensuremath{\gg}({\ensuremath{\gamma}}_{eg},\ensuremath{\Gamma},{\ensuremath{\gamma}}_{\ensuremath{\phi}})]$ and the long coherence time ($\ensuremath{\sim}{10}^{\ensuremath{-}3}$ s) of the N-VVV centers, the quantum information can be stored in the memory steadily, and it can be retrieved with a high fidelity (>96>96%>96). This scheme provides a scalable way of exchanging quantum information between different quantum interfaces, and has the experimental feasibility with currently available experimental technology.
We report the experimental realization of a hybrid quantum circuit combining a superconducting qubit and an ensemble of electronic spins. The qubit, of the transmon type, is coherently coupled to the spin ensemble consisting of nitrogen-vacancy centers in a diamond crystal via a frequency-tunable superconducting resonator acting as a quantum bus. Using this circuit, we prepare a superposition of the qubit states that we store into collective excitations of the spin ensemble and retrieve back into the qubit later on. These results constitute a proof of concept of spin-ensemble based quantum memory for superconducting qubits.
We present a technique to store and retrieve single- and two-qubit states into a parity-protected quantum memory implemented on a state-of-the-art superconducting circuit architecture. Our proposal relies upon a specific superconducting circuit design that permits a tunable qubit-resonator coupling strength. The latter allows us to adiabatically tune from the weak coupling to the ultrastrong coupling regime of light-matter interaction, where a controllable and well-protected effective two-level system is defined due to the Z2 parity symmetry. Storage and retrieval time of the qubit are in a few nanoseconds timescale, which is far below the effective qubit coherence time.
We have built a hybrid system composed of a superconducting flux qubit (the processor) and an ensemble of nitrogen-vacancy centers in diamond (the memory) that can be directly coupled to one another, and demonstrated how information can be transferred from the flux qubit to the memory, stored, and subsequently retrieved. We have established the coherence properties of the memory and succeeded in creating an entangled state between the processor and memory, demonstrating how the entangled state's coherence is preserved. Our results are a significant step towards using an electron spin ensemble as a quantum memory for superconducting qubits.