Description:
OUSD (R&E) CRITICAL TECHNOLOGY AREA(S): Quantum Science
OBJECTIVE: This program seeks to develop a stable, resonant rf circuit for trapped ion systems that is resistant to environmental perturbations such as ambient temperature changes and vibration.
DESCRIPTION: Isolated, trapped atomic ions are among the leading candidates to realize quantum computing and quantum networking systems. Trapped ions are confined using high voltage rf electric fields to isolate the ions from the external environment. The confining potential determines the normal mode frequencies of vibration of a chain of trapped ions; typical rf resonant circuits (Q = 200 – 500) apply a single frequency in the 10 – 100 MHz range with an rf amplitude of approximately 250 – 500 volts, depending on the ion trap. Stabilizing the trapped ion normal mode frequencies, proportional to the ratio of the applied voltage to the rf drive frequency, can play a key role in enabling high-fidelity entangling gates between trapped ions while allowing higher speed entangling gates. Using active feedback, these circuits have been stabilized to approximately 10 ppm in a pristine, laboratory setting with small variations in temperature and minimal vibration [1].
PHASE I: This topic is accepting Direct to Phase II proposals only. The proposer must provide a report or documentation showing the feasibility of the proposed approach. Such a report could be based on measured performance of an early prototype device (whether connected to an ion-trap stand-in load or an ion trap). If iterating on an existing design with measured performance lower than the specifications below, offeror should identify the key design changes leading to the expected improvement in performance, along with applicable simulation and/or modeling. For new designs, the approach should be documented with simulations and/or modeling showing the expected performance for the proposed design.
PHASE II: This project will develop a laboratory prototype device (not necessarily a quarter wave helical resonator) that results in an applied rf field to an ion trap where a trapped ion’s secular frequency should be stable. To accomplish this, the ratio of the rf voltage amplitude to the drive frequency should vary by less than 1 x 10^-5 if the ambient air temperature varies by +/- 3 C. This stability should also be maintained if the device is subjected to acoustic noise in the audio range at levels of approximately 60 dB.
The resonator shall be tested by measuring the stability of an ion trap's transverse secular frequency. The measurement should be performed optically by probing an ion sideband of motion probing a narrow transition (ex: Raman or quadrupole) to enable the required precision for characterizing the resonator performance. This measurement can be done in-house or by external partnership. In addition, a final report detailing the design and testing should be made available. This report could take the form of a publication if appropriate. Phase II Base amount must not exceed $700,000 for a 12-month period of performance and the Option amount must not exceed $300,000 for a 6-month period of performance.
PHASE III DUAL USE APPLICATIONS: Phase III potential applications: This rf resonator circuit with enhanced resistance to environmental perturbations can be commercialized and used on commercial trapped ion systems as well as DoD trapped ion systems. The development of trapped ion systems is aligned with DoD goals to develop quantum information technology to enhance position, navigation, timing, and secure communication. Generally, this technology could be used where there is a need to supply high voltage at radiofrequencies to a low impedance electrical load.
REFERENCES:
1. “Active Stabilization of Ion Trap Radiofrequency Potentials,” K. G. Johnson, J. D. Wong-Campos, A. Restelli, K. A. Landsman, B. Neyenhuis, J. Mizrahi, and C. Monroe, Rev. Sci. Instrum. 87, 053110 (2016); arXiv:1603.05492v2
2. “Electromagnetic traps for charged and neutral particles”, W. Paul, Rev. Mod. Phys, 62, 531,(1990).
3. “Realization of a Filter with Helical Components”, A. I. Zverev and H. J. Blinchikoff, IRE Trans. Compon. Parts, 99 (1961).
4. “Coaxial Resonators with Helical Inner Conductor,” W. W. MacAlpine and R. O. Schildknecht, Proc. IRE, 2099 (1959).
5. Siverns, J.D., Simkins, L.R., Weidt, S. et al. On the application of radio frequency voltages to ion traps via helical resonators. Appl. Phys. B 107, 921–934 (2012).; arXiv:1106.5013v3
KEYWORDS: Ion trap; entanglement; quantum gates; rf resonator; high-fidelity; quantum computing; quantum network
