Ted White

A 28nm Bulk-CMOS 4-to-8GHz <2mW Cryogenic Pulse Modulator for Scalable Quantum Computing

  1. Joseph C Bardin,
  2. Evan Jeffrey,
  3. Erik Lucero,
  4. Trent Huang,
  5. Ofer Naaman,
  6. Rami Barends,
  7. Ted White,
  8. Marissa Giustina,
  9. Daniel Sank,
  10. Pedram Roushan,
  11. Kunal Arya,
  12. Benjamin Chiaro,
  13. Julian Kelly,
  14. Jimmy Chen,
  15. Brian Burkett,
  16. Yu Chen,
  17. Andrew Dunsworth,
  18. Austin Fowler,
  19. Brooks Foxen,
  20. Craig Gidney,
  21. Rob Graff,
  22. Paul Klimov,
  23. Josh Mutus,
  24. Matthew McEwen,
  25. Anthony Megrant,
  26. Matthew Neeley,
  27. Charles Neill,
  28. Chris Quintana,
  29. Amit Vainsencher,
  30. Hartmut Neven,
  31. and John Martinis
Future quantum computing systems will require cryogenic integrated circuits to control and measure millions of qubits. In this paper, we report the design and characterization of a
prototype cryogenic CMOS integrated circuit that has been optimized for the control of transmon qubits. The circuit has been integrated into a quantum measurement setup and its performance has been validated through multiple quantum control experiments.
arxiv pdf

Strong environmental coupling in a Josephson parametric amplifier

  1. Josh Mutus,
  2. Ted White,
  3. Rami Barends,
  4. Yu Chen,
  5. Zijun Chen,
  6. Ben Chiaro,
  7. Andrew Dunsworth,
  8. Evan Jeffrey,
  9. Julian Kelly,
  10. Anthony Megrant,
  11. Charles Neill,
  12. Peter O'Malley,
  13. Pedram Roushan,
  14. Daniel Sank,
  15. Amit Vainsencher,
  16. James Wenner,
  17. Kyle Sundqvist,
  18. Andrew Cleland,
  19. and John Martinis
We present a lumped-element Josephson parametric amplifier designed to operate with strong coupling to the environment. In this regime, we observe broadband frequency dependent amplification
with multi-peaked gain profiles. We account for this behaviour using the „pumpistor“ model which allows for frequency dependent variation of the external impedance. Using this understanding, we demonstrate control over gain profiles through changes in the environment impedance at a given frequency. With strong coupling to a suitable external impedance we observe a significant increase in dynamic range, and large amplification bandwidth up to 700 MHz giving near quantum-limited performance.
arxiv pdf

Design and characterization of a lumped element single-ended superconducting microwave parametric amplifier with on-chip flux bias line

  1. Josh Mutus,
  2. Ted White,
  3. Evan Jeffery,
  4. Daniel Sank,
  5. Rami Barends,
  6. Joerg Bochmann,
  7. Yu Chen,
  8. Zijun Chen,
  9. Ben Chiaro,
  10. Andrew Dunsworth,
  11. Julian Kelly,
  12. Anthony Megrant,
  13. Charles Neill,
  14. Peter O'malley,
  15. Pedram Roushan,
  16. Amit Vainsencher,
  17. Jim Wenner,
  18. Irfan Siddiqi,
  19. Rajamani Vijayaraghavan,
  20. Andrew Cleland,
  21. and John Martinis
We demonstrate a lumped-element Josephson Parametric Amplifier (LJPA), using a single-ended design that includes an on-chip, high-bandwidth flux bias line. The amplifier can be pumped
into its region of parametric gain through either the input port or through the flux bias line. Broadband amplification is achieved at a tunable frequency $\omega/2 \pi$ between 5 to 7 GHz with quantum-limited noise performance, a gain-bandwidth product greater than 500 MHz, and an input saturation power in excess of -120 dBm. The bias line allows fast frequency tuning of the amplifier, with variations of hundreds of MHz over time scales shorter than 10 ns.
arxiv pdf

Computing prime factors with a Josephson phase qubit quantum processor

  1. Erik Lucero,
  2. Rami Barends,
  3. Yu Chen,
  4. Julian Kelly,
  5. Matteo Mariantoni,
  6. Anthony Megrant,
  7. Peter O'Malley,
  8. Daniel Sank,
  9. Amit Vainsencher,
  10. James Wenner,
  11. Ted White,
  12. Yi Yin,
  13. Andrew N. Cleland,
  14. and John M. Martinis
. Compiled versions of Shor’s algorithm have been demonstrated"]on ensemble quantum systems[2] and photonic systems[3-5], however this has yet to be shown using solid state quantum bits (qubits). Two advantages of superconducting qubit architectures are the use of conventional microfabrication techniques, which allow straightforward scaling to large numbers of qubits, and a toolkit of circuit elements that can be used to engineer a variety of qubit types and interactions[6, 7]. Using a number of recent qubit control and hardware advances [7-13], here we demonstrate a nine-quantum-element solid-state QuP and show three experiments to highlight its capabilities. We begin by characterizing the device with spectroscopy. Next, we produces coherent interactions between five qubits and verify bi- and tripartite entanglement via quantum state tomography (QST) [8, 12, 14, 15]. In the final experiment, we run a three-qubit compiled version of Shor’s algorithm to factor the number 15, and successfully find the prime factors 48% of the time. Improvements in the superconducting qubit coherence times and more complex circuits should provide the resources necessary to factor larger composite numbers and run more intricate quantum algorithms.
arxiv pdf