Techniques for transduction and storage of quantum level signals

Abstract

Embodiments described herein include systems and techniques for converting (i.e., transducing) a quantum-level (e.g., single photon) signal between the three wave forms (i.e., optical, acoustic, and microwave). A suspended crystalline structure is used at the nanometer scale to accomplish the desired behavior of the system as described in detail herein. Transducers that use a common acoustic intermediary transform optical signals to acoustic signals and vice versa as well as microwave signals to acoustic signals and vice versa. Other embodiments described herein include systems and techniques for storing a qubit in phonon memory having an extended coherence time. A suspended crystalline structure with specific geometric design is used at the nanometer scale to accomplish the desired behavior of the system.

What is claimed is: 
     
         1 . A system, comprising:
 a mechanical resonator; and   a circuit coupled to the mechanical resonator;   wherein the circuit is configured to coherently excite hypersonic mechanical motion of the mechanical resonator so as to transfer a quantum level signal for storage in the mechanical resonator.   
     
     
         2 . The system of  claim 1 , wherein the circuit is configured to coherently excite the hypersonic mechanical motion of the mechanical resonator so as to transfer the quantum level signal for storage in the mechanical resonator with a Q factor of at least 10 6 . 
     
     
         3 . The system of  claim 1 , further comprising a waveguide coupled to the circuit, wherein phonons dissipate from the mechanical resonator via leakage of a photon from the circuit through the waveguide. 
     
     
         4 . The system of  claim 1 , wherein the circuit comprises a microwave circuit, the hypersonic mechanical motion comprises a mode at a gigahertz frequency, and the microwave circuit and the mechanical resonator are coupled via a cooperative coupling of at least 30. 
     
     
         5 . The system of  claim 1 , wherein the circuit comprises a superconducting microwave circuit and the quantum level signal comprises a superposition state. 
     
     
         6 . The system of  claim 1 , wherein the circuit controls a detuning of a drive tone relative to resonant modes of the circuit, so as to control the storage and a readout of the quantum level signal. 
     
     
         7 . The system of  claim 1 , wherein the circuit is configured to define an operating bandwidth of the system. 
     
     
         8 . The system of  claim 1 , wherein the mechanical resonator comprises a nano-mechanical resonator. 
     
     
         9 . The system of  claim 8  wherein the nano-mechanical resonator comprises a nanobeam. 
     
     
         10 . The system of  claim 1 , wherein the mechanical resonator comprises a chain of acoustic cavities or a linear resonator. 
     
     
         11 . The system of  claim 1 , wherein the mechanical resonator comprises a piezoelectric nanomechanical resonator. 
     
     
         12 . The system of  claim 1 , wherein the mechanical resonator comprises a phononic crystal comprising a phononic bandgap suppressing or eliminating acoustic radiation from the mechanical resonator other than via the circuit. 
     
     
         13 . The system of  claim 1 , wherein the circuit transfers the quantum level signal comprising a qubit suitable for processing in a quantum computer. 
     
     
         14 . The system of  claim 1 , wherein the circuit is configured to readout the qubit stored in the mechanical resonator. 
     
     
         15 . The system of  claim 1 , wherein the circuit is configured to transfer the quantum level signal via a parametric interaction. 
     
     
         16 . The system of  claim 1 , comprising a transducer transducing the quantum level signal between an electrical form in the circuit and an acoustic form in the mechanical resonator. 
     
     
         17 . A network comprising the transducer of  claim 16 , wherein the network distributes quantum information using the quantum level signal. 
     
     
         18 . The system of  claim 1 , comprising a transducer transducing the quantum level signal into an optical signal. 
     
     
         19 . A network comprising the transducer of  claim 18 , wherein the network distributes quantum information using the optical signal. 
     
     
         20 . The system of  claim 1 , further comprising a metamaterial. 
     
     
         21 . A method of storing quantum level signals, comprising:
 coherently exciting a hypersonic mechanical motion of a mechanical resonator, so as to transfer a quantum level signal for storage in the mechanical resonator with a Q factor of at least 10 6 ; and   removing phonons from the mechanical resonator via leakage of photons from a circuit coupled to the mechanical resonator.