State and Signal Tracking with Quantum Measurement
Abstract
State and Signal Tracking with Quantum MeasurementGrant to PI Kater MurchWashington Univ of St LouisKater MurchAssistant Professor, Physics Department,Campus Box 1105, Washington UniversityOne Brookings Dr., St. Louis, MO, 63130phone: (314) 935-7765, fax: (314) 935-6219email: murch@physics.wustl.eduobjective: The objective is to test the applicability of a recently invented Bayesian approach to understanding the quantum measurement process to the case of the probabilistic switching of a Josephson junction based current comparator biased in its ~grey zone~. approach: The time correlation of reported samples from single and paired comparators looking at the same input signal will be experimentally measured with resolution to 20 ps and the Bayesian method used to attempt reconstruction of the input signal from the single bit data corresponding to sub-mircosecond events. A better understood but conceptually identical problem from the arena of quantum non-demolition measurement in quantum computing will also be worked and the algorithms for the Bayesian technique~s realization further worked.short work: Funds are provided to advance the state of the art regarding back calculation of the temporal history of a state system, and especially determination of its initial state, following repeated measurement with probabilistic tools of its instantaneous state. ONR mission relevance: Extreme precision measurements often depend on quantum mechanical processes which are formally described only by probabilistic functions. Run forward, these sensors deliver reliable answers when enough trials have been run to determine the ensemble average result. When the quantum sensor is a Josephson junction based current comparator in an analog to digital converter, that ensemble might be a 1 microsecond worth of ultra wide band spectral energy that when digitally processed can produce a 1 MHz FFT bin width display of the entire input spectrum. But our classical intuition still desires to know what the time domain representation of the spectrum looks like on the nanosecond or shorter time scale. Answering that question requires us to understand how to reduce the large noise present in individual measurements using its close in time neighbors. Enabling improved time domain signal reconstruction is the ultimate technical goal of this work. Tech merit: Dr Murch is an extremely talented, early career physicist working primarily on superconducting quantum computing, especially on the issue of qubit state read-out using quantum non-demolition techniques. The Bayesian method of improving our understanding of the evolution of quantum states in a single system was invented at the end of his postdoc in that context and is a seminal step forward in the world of quantum measurement theory. This grant will allow him to further develop the technique in its original setting and test its applicability to the analog to digital converter issue of much more immediate relevance to RF receivers and information dominance. Dr Murch is probably the only person in the West who could do this work and is a US citizen by birth. He has agreed to utilize a native born American graduate student in this work. The QC portion will definitely be published in the open literature as is appropriate for basic research.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Aug 12, 2016
- Source ID
- N000141612638
Entities
People
- Kater Murch
Organizations
- Office of Naval Research
- United States Navy
- Washington University in St. Louis