OBJECTIVES:

1
Center for Quantum Information ROCHESTER HARVARD
CORNELL STANFORD RUTGERS LUCENT TECHNOLOGIES

• OBJECTIVES
• To use simple, scalable mesoscopic elements such
  as quantum point contacts and quantum dots for
  manipulation of spin entanglement.
• RELEVANCE
• Submicron fabrication of coherent structures in
  clean semi-conductors is highly developed and
  currently offers the best hope for scalable
  quantum information processing. The 2D character
  of the heterostructure allows spin to be
  manipulated in a straightforward way.
  Confinement on submicron scales provides a new
  set of tool to produce entanglement of electrons
  including direct spin exchange and Kondo-like
  mediated exchange.
• ACCOMPLISHMENTS (Past Year)
• Discovery of Kondo-like entangled state in a GaAs
  Quantum Point Contact.
• First demonstration of spin effect in paired
  point contacts
• First demonstration of spin injection and
  detection using a quantum point contact focusing
  geometry.

Coherent Semiconductor Nanoelectronics
Group MarcusLab, Harvard University
Discovery a simple QPC is a Kondo-like spin
entangled system at low temperatures
0.7 structure in a quantum point contact
Cronenwett, CMM et al. (PRL, in press).

Scaling of temperature dependence of point
contact conductance to modified Kondo form.
An array of QPCs as an entangled spin chain
Spin injector-detector experiment. In a parallel
field, the quantum dot should act as a
gate-tunable spin filter.