IARPA seeking improved superconducting qubits and fault diagnostics and annealing test beds

The Intelligence Advanced Research Projects Activity (IARPA) hosted a Proposers’ Day Conference for the QEO [Quantum Enhanced Optimization] program on October 26, 2015, in anticipation of the release of a new solicitation.

Quantum Enhanced Optimization Program Description and Goals

QEO seeks to harness quantum effects required to enhance quantum annealing solutions to hard combinatorial optimization problems. The physics underlying quantum enhancement will be corroborated by design and demonstration of research-scale annealing test beds; comprised of novel superconducting qubits, architectures, and operating procedures. All work will serve to demonstrate a plausible path to enhancement and a basis for design of application-scale quantum annealers.

The QEO Program is anticipated to focus on the following specific applications problems:

1. Fault diagnostics, and specifically problems related to a 16×16 multiplier CRC, i.e. circuit C6288, described in detail at http://web.eecs.umich.edu/~jhayes/iscas.restore/c6288.html; and
2. k-SAT, and at minimum 3-SAT, for problems including search filter design, and other significant problems where k-SAT offers compelling performance; and
3. Machine-task / job-shop type scheduling, and or circuit layout.

The QEO program is divided into two phases. Phase 1 will run for a period of 36 months, followed by Phase 2 at 24 months.

QEO seeks to develop theoretical and experimental capability to design, fabricate, analyze, and optimize quantum annealing Test Beds. QEO performers will corroborate innovative concepts and predictive models of enhancement through Test Bed experiments; demonstrating how enhancement is optimally promoted by design and operation, and estimating the elements of design for application-scale machines.

From all developments, the goal of the QEO Program is to provide a physical basis of design for application-scale quantum annealers providing a 10,000 speed-up with polynomial improvement in scaling complexity over classical methods.

To meet the program goal, QEO will explore a wide range of highly advanced quantum annealing capabilities, including:

  • Physical-Spin-Qubits with high, tunable coherence and function;
  • Advanced quantum fluctuations (e.g., multi-spin);
  • Broader classes of spin connectivity and physical architectures to access a broader, harder, problem space (e.g., simultaneous long-range and multi-spin interactions, higher intrinsic connectivity);
  • Real-time measurements during the annealing protocol to elucidate quantum enhancement phenomena and optimize both design and dynamic operation for performance;
  • Advanced annealing protocols (e.g., spatially-varying fields and couplings, adaptive control methods based on feedback, active qubit cooling);
  • Quantum error mitigation: error suppression, as well as engineered dissipation and cooling;
  • Greater precision, stability, and speed of calibration and control signals using state-of-art electronics;
  • Smart integration that optimizes the separate quantum (coherent Ising spins and couplings) and classical (control and readout) elements of the annealing system

Different from LogiQ – Logical Qubit program

IARPA is seeking innovative solutions for the Logical Qubits (LogiQ) Program. LogiQ intends to build a logical qubit from a number of imperfect physical qubits by combining high-fidelity multi-qubit operations with extensible integration. The LogiQ Program is envisioned to begin 1 February 2016 and end by 31 January 2021.

Current quantum computing systems have important limitations that hinder their path to fault-tolerant quantum computation. First and foremost, the overall performance of multi-qubit systems is inferior to the performance of the individual qubits. These physical qubits are susceptible to system noise and losses induced by their environment, insufficient operation fidelity, lack of error correction, poor feedback and dynamical control, and inadequate multi-qubit control. Success in building practical quantum computers hinges on the ability to combat environment-induced decoherence and errors in quantum gates. This can be effectively and extensibly achieved by innovations that encode physical qubits into a logical qubit.

The Logical Qubits (LogiQ) Program seeks to overcome the limitations of current multi-qubit systems, described in the previous paragraph, by building a logical qubit from a number of imperfect physical qubits. LogiQ envisions that program success will require a multi-disciplinary approach that increases the fidelity of quantum gates, state preparation, and qubit readout; improves classical control; implements active quantum feedback; has the ability to reset and reuse qubits; and performs further system improvements.

Additionally, LogiQ seeks a modular architecture design of two coupled logical qubits that creates a flexible and feasible path to larger systems. Modular designs facilitate the incorporation of next-generation advances with minimal constraints, while maintaining or improving performance.

Researchers at IARPA and IBM have been working on the logical qubit issue with some success. IBM scientists announced in April that they had developed a new qubit circuit design that is claimed to be the only physical architecture that could successfully scale to larger dimensions.

Nature Communication – Demonstration of a quantum error detection code using a square lattice of four superconducting qubits

SOURCES – FCW Business of Federal Technology, FBO.gov, Nature Communication

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