From left: Brian
Zhou, Christopher Yale and F. Joseph Heremans, researchers at the
University of
Chicago’s Institute for Molecular Engineering, and the optical apparatus
they used to
control geometric phases in diamond. Courtesy of Awschalom Group
(February 19, 2016) Scientists demonstrate versatile,
noise-tolerant quantum operations on a single electron
While a classical bit found in conventional electronics
exists only in binary one or zero states, the more resourceful quantum bit, or
‘qubit,’ is represented by a vector, pointing to a simultaneous combination of
the one and zero states. To fully implement a qubit, it is necessary to control
the direction of this qubit’s vector, which is generally done using fine-tuned
and noise-isolated procedures.
Researchers at the University of Chicago’s Institute for
Molecular Engineering and the University of Konstanz have demonstrated the
ability to generate a quantum logic operation, or rotation of the qubit,
that—surprisingly—is intrinsically resilient to noise as well as to variations
in the strength or duration of the control. Their achievement is based on a
geometric concept known as the Berry phase and is implemented through entirely
optical means within a single electronic spin in diamond.
Their findings were published online Feb. 15, 2016, in
Nature Photonics and will appear in the March print issue. “We tend to view
quantum operations as very fragile and susceptible to noise, especially when
compared to conventional electronics,” remarked David Awschalom, the Liew
Family Professor of Molecular Engineering and senior scientist at Argonne
National Laboratory, who led the research. “In contrast, our approach shows
incredible resilience to external influences and fulfills a key requirement for
any practical quantum technology.”