Quantum Information: Theory and Applications

Quantum Information: Theory and Applications

Fig: Projection of 3D colour codes onto 3D toric codes

  • Quantum Error Correction
  • Quantum Algorithms
  • Quantum Dynamics
  • Quantum Machine Learning
  • Quantum Cryptography

Quantum Computing

Quantum Computing

Fig: Expt setup of a Poor Man’s Ising machine

Photonic Quantum Computing was one of the first paradigms explored for quantum computing. However, issues of scalability tilted the balance in favour of solid state technologies. Recent improvements in Si photonics has driven interest back towards photonics platforms with a number of startup ventures (e.g. Xanadu, PsiQuantum) in the fray.  Photonics is naturally suited for communications, but is also useful for

  • Coherent Ising Machines (CIMs)
    • Temporal multiplexing of wave packets
    • Spatial multiplexing of wave functions
  • Measurement based Quantum Computing (MBQC)
  • Boson Sampling

Quantum Communications

Quantum Communications

Fig: DPS QKD demonstrated over 105 km

Quantum Communications allows us to use the quantum properties of photons to transfer information between multiple parties. It offers the promise of unconditionally secure communications through quantum key distribution (QKD). Of particular interest to us are

  • Fibre based QKD systems at 1550 nm
  • Free space optical (FSO) systems at 800 nm

QKD is based around a number of protocols and implementations

  • BB84, E91, B92, COW, MDI
  • polarization, distributed phase, entanglement

There is also interest in developing ideas for

  • metro area quantum access networks (MAQAN)
  • quantum secret sharing (QSS)
  • quantum time synchronized information (QTSI)
  • quantum security verification

Silicon Photonics

Silicon Photonics

Fig: Adiabatic Spot Size Convertor between Rib Waveguide and SWG Wavguide

Silicon photonics is CMOS compatible and is used to miniaturize a number of quantum technologies, such as

  • quantum random number generators
  • intecrated circuit chips for quantum key distribution
  • boson sampling
  • measurement based quantum computing (MBQC)

Diamond Photonics

Diamond Photonics

Fig: Optically interrogating nano-diamonds

Nitrogen and silicon vacancies in diamond are used for

At C-QuICC, we have a growing list of active projects in all these areas