Back to the Basic: Spin Maser for Quantum Information Technologies

2020.5.20

OIST, Yuimaru Kubo

Current quantum information technologies at microwave frequencies require
ultra-low temperature operations, typically at 10 – 100 millikelvin, because of
the tiny energy of microwave photons.  One of the key technologies is an
ultra-low noise amplification of microwave signals at millikelvin
environments.  This has only been realized by superconducting Josephson
parametric amplifiers (JPA), which are based on superconducting circuits. 
However, JPAs have suffered from a smaller saturation power. The
state-of-the-art JPA has a maximum input power of about -100 dBm (0.1 picowatts). 
Moreover, JPAs do not properly work under strong magnetic fields due to the
superconductivity. 

One

Two-mode thermal squeezing in a mechanical resonator based on a nonlinear measurement

2020.3.23

Motoki Asano and Hiroshi Yamaguchi, NTT Basic Research Laboratories

Multiple mechanical modes in a micro/nano mechanical resonator show a random motion due to thermal fluctuation. Producing a correlation among the modes is applicable for sensing and information processing with squeezing the thermal noise. We demonstrated a novel squeezing scheme based on an optical nonlinear measurement of mechanical oscillators. So far, the noise squeezing has been performed by making a polarization in a pseudo-angular momentum with a sum-frequency pump signal. We clarified that the noise squeezing is enabled by directly

Experimental demonstration of plasmonic quantum walks in the one-dimensional gold-strip waveguide lattice structure

2019.12.13

  Shuichiro Inoue, Nihon University

Quantum walks (QWs) simulate quantum mechanical behaviours of particles, which exhibit time evolutions completely different from the classical random walks. QWs offer quantum physical simulations and the novel approach to build quantum computers. Currently on-chip photonic devices have been intensively developed and QWs have been implemented using photonic circuits based on silica waveguide platforms.

We have experimentally demonstrated QWs in
one-dimensional lattice structures based on the long-range surface plasmon
polariton (LR-SPP) waveguide platform. The LR-SPP waveguide allows a
single-polarization mode, and has relatively low optical losses. The

Generation of high-repetition rate sub-cycle mid-infrared pulses applicable to lightwave-driven STM

2019.11.25

Yokohama National
University, Jun Takeda

Lightwave-driven
scanning tunneling microscopy (STM) has been realized using
carrier-envelope-phase (CEP)-stable THz pulses, and electron tunneling was
coherently manipulated across a tunnel junction.

Robust control of two-qubit Hamiltonian dynamics

2019.11.13

Mio Murao, The University of Tokyo

We showed that it is possible to achieve robust control of Hamiltonian dynamics to implement an arbitrary target quantum gate for two-qubit Hamiltonian systems including an unknown parameter by adding a single-qubit control Hamiltonian.