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Previous projects

Super-Bloch Oscillations

Electron Qubits in Silicon

Quantum Chaotic Ratchets

AC-driven BECs

Double-Kicked Atoms


Earlier Work 1990-99

Rydberg Atoms in strong fields

Rydberg Molecules in external fields

Chaos and Tunnelling Diodes


We are theorists investigating the behaviour of quantum systems which are promising candidates for the development of future quantum technologies, such as quantum computers and quantum sensors. We are part of the UCL optomechanics group. A key goal is an experiment-theory collaborative project which aims to cool a small mechanical oscillator down to its quantum ground state. In the UCL group, small silica spheres and nanodiamonds levitated in optical fields are being cooled inside a high finesse cavity.
We also investigate quantum spin dynamics with a view to understand and control their quantum coherence. One motivation is the possibility to extend powerful techniques such as NMR and MRI down to the single spin level. Single-spin sensing techniques are advancing rapidly, but there is a need to optimise the extraction of information on the atomic scale structure from experimental measurement of the quantum coherence. We investigate also how quantum spins qubits interact with the surrounding environment. Typically, the environment are other quantum spins so the back-action between environment and target spin, and entanglement between them makes the behaviour very different from the more typical situation where a quantum particle loses coherence through its interaction with environmental noise which is classical in nature.

There are potential PhD opportunities in the following areas:
(1) Optomechanics: towards sensing at the quantum limit
(2) Quantum spin dynamics: single spin sensing and decoherence.

We welcome enquiries from prospective PhD students or other researchers and visitors.
For further information contact: Prof. T S Monteiro: TEL.+44 (020)7679 3504

NV centres in diamond.


Coherence 'diamonds'
Single-spin sensing
for an NV center in diamond

Coherence Map
for bismuth in silicon

A new approach to aid analysis of spin sensing experiments has been developed. The experimental features arising from periodically repeated sequences, such as CPMG sequences illustrated above, are analysed in terms of an underlying quantum Floquet spectrum. This allows greater flexibility in detecting more complex situations such as many-body interactions, strong coupling and pulses of finite duration
Jacob E. Lang, Renbao Liu and T. S. Monteiro
Phys. Rev. X 5, 041016 (2015)

We develop theory and models
hybridT2.” TARGET=

for the hybrid trap experiment

The UCL Hybrid Trap
aims to cool a levitated nano particle to its quantum ground state

Schlumberger Fellow
Ms Erika Aranas has joined the project.

From our recent paper "Cavity cooling a single charged nanosphere"
Phys.Rev.Lett. 114 123602 (2015). see also Physics Focus

Seto Balian and Jacob Lang
hybridT2.” TARGET=

visiting Renbao Liu in Hong Kong.

Dr S. J. Balian!!
and colleagues August 2015 viva

Setrak has graduated
and gone to California UCSD.

Goodbye Seto!!! After 4 great years, Seto Balian has graduated and left for a postdoc in California.

In the past we have investigated a range of nonlinear and quantum dynamical behaviours in atomic, molecular and solid-state systems, including quantum behaviour of systems which exhibit chaos in the classical limit.


Classical vs Quantum phase space (Wigner functions) of atomic electron in a strong magnetic field: (a)chaotic(b)mixed(c)regular


Bifurcations of electronic orbits in the RTD.

Tunnelling Diodes

Rydberg Atoms in
Atoms in external fields
external fields

Rydberg Molecules in
of H2 in a
magnetic fields