RESEARCH
My research activity has been mainly focused on mesoscopic and
molecular systems of interest for the implementation of quantum devices,
namely semiconductor quantum dots (QDs) and molecular magnets (MMs).
n particular, I've worked at the modelization of such systems; at the elaboration
of schemes for their coherent manipulation and for the implementation of quantum
logical gates; and at the simulation of their dynamics, with the inclusion of
the relevant decoherence processes.
SEMICONDUCTOR QUANTUM DOTS (QDs)
• Modelization. Numerical calculation of the carrier
confined states, including the effect of external (electric
and magnetic) fields and of coherent interdot coupling, within
the effectivemass approximation. Calculation of the corresponding
fewparticle states, by means of a configuration interaction
technique. Optical properties associated with transition between
such states, and their dependence on possible charging effects.
Tuning of the interdot coupling, and of the resulting interdot
correlations, through the application of external fields.
• Coherent manipulation and decoherence processes.
Schemes for the coherent optical manipulation (based on stimulated
Raman adiabatic passage) of a charged carrier in coupled
QDs. Relaxation in coupled QDs related to phonon emission,
and its suppression by means of electric and magnetic fields.
• Encoding and manipulation of quantum information.
Proposal based on the qubit encoding in the excitonic degrees
of freedom, and on their manipulation through sequences of
ultrafast laser pulses. Proposal based on the qubit identification
with the electronic spin, and on its alloptical manipulation
by means of stimulated Raman transitions.
QUANTUM DOTS IN OPTICAL MICROCAVITIES (MCs)
• Sources of nonclassical light. QDMC systems
as sources of single photons on demand: limitations to the
photon indistinguishability arising from the decoerence processes
and from the incoherent nature of the pumping. Simulation,
within the densitymatrix formalism, of quantum tomography
experiments, and calculation of the corresponding concurrence
in photon pairs generated by QD cascade emission.
• Single spin readout. Proposal and simulation
of optical (quantum nondemolition) measurement for a single
carrier spin in a QDMC system. The scheme relies on the controlled
entanglement between the spin state and the polarization of
cavity photons.
MOLECULAR MAGNETS (MM):
• Encoding and manipulation of quantum information.
Qubit encoding in antiferromagnetic MMs (namely, heterometallic
rings and triangles), and molecule modelling through spin
Hamiltonians. Schemes for the implementation of (one and
twoqubit) quantum gates, in the absence of local fields and
of tuneable intermolecular couplings.
• Decoherence. Loss of phase coherence in heterometallic
MMs as a consequence of the hyperfine interactions between
the magnetic ions and the nuclear environment. Electronnuclear
reversibility by spinecho sequences.
• Electric spin control. Pulsed electric fields as an alternative route to electron spin manipulation in antiferromagnetic molecular magnets.
LIST OF PUBLICATIONS
MAIN SCIENTIFIC PUBLICATIONS
 M. Trif, F. Troiani, D. Stepanenko, and D. Loss,
"Spinelectric coupling in molecular magnets", Phys.
Rev. Lett., 101, 217201 (2008).
 G. A. Timco, S. Carretta, F. Troiani, F. Tuna,
R. J. Pritchard, E. J. L. McInnes, A. Ghirri, A. Candini,
P Santini, G. Amoretti, M. Affronte and R. E. P. Winpenny,
"Engineering coupling between molecular spin qubits by supramolecular
chemistry", Nature
Nanotech. 4, 173 (2009).
 M. Abbarchi, F. Troiani, C. Mastrandrea, G. Goldoni,
T. Kuroda, T. Mano, K. Sakoda, N. Koguchi, S. Sanguinetti,
A. Vinattieri, and M. Gurioli, "Sprectral diffusion and
line broadening in single selfassembled GaAs/AlGaAs quantum
dot photoluminescence", Appl. Phys. Lett. 93,
162101 (2008).
 S. Shojaei, F. Troiani, A. Asgari, M. Kalafi,
G. Goldoni "Coulombinduced nonlinearities in GaN microdisks"
The European Phys. J. B 65, 505 (2008).
 E. Cancellieri, F. Troiani, and G. Goldoni, "Indistinguishable
photons from different quantum dots: an optimization approach
based on evolutionary programming", submitted (2008).
 F. Troiani and C. Tejedor, "Entangled photon pairs
from a quantum dot cascade decay: the effect of time reordering",
Phys. Rev. B 78, 155305 (2008).
 D. M. Tomecka, V. Bellini, F. Troiani, F. Manghi,
G. Kamieniarz, and M. Affronte, "Ab initio study on a chain
model of the Cr8 molecular magnet", Phys. Rev. B 77, 224401
(2008).
 F. Troiani, V. Bellini, and M. Affronte, "Electronspin
decoherence in antiferromagnetic molecular rings: the effect
of hyperfine interactions", Phys. Rev. B 77, 054428 (2008).
 E. del Valle, F. P. Laussy, F. Troiani, and C.
Tejedor, "Entanglement and lasing with two quantum dots
in a microcavity", Phys. Rev. B 76, 235317 (2007).
 S. Carretta, P. Santini, G. Amoretti, F. Troiani,
M. Affronte, "Spin triangles as optimal units for moleculebased
quantum gates", Phys. Rev. B 76, 24408 (2007).
 J. I. Perea, F. Troiani, and C. Tejedor, "Correlated
photonpair emission from pulsepumped quantum dots embedded
in a microcavity", Solid State Commun. 144,
542 (2007).
 F. Troiani, I. WilsonRae, and C. Tejedor, "Alloptical
nondemolition measurement of singlehole spin in a quantumdot
molecule", Appl. Phys. Lett. 90, 144103 (2007).
 A. Bertoni, M. Rontani, G. Goldoni, F. Troiani,
E. Molinari, Response to "Comment on `Fieldcontrolled suppression
of phononinduced transitions in coupled quantum dots' [Appl.
Phys. Lett. 88, 4729 (2006)]", Appl. Phys. Lett. 88, 196102
(2006).
 F. Troiani, J. I. Perea, and C. Tejedor, "Cavityassisted
generation of entangled photon pairs by a quantumdot cascade
decay", Phys. Rev. B 74, 235310 (2006).
 U. Hohenester, J. Fabian, and F. Troiani, "Adiabatic
Passage Schemes in Coupled Semiconductor Nanostructures",
Optics Communications 264, 426 (2006).
 F. Troiani, J. I. Perea, and C. Tejedor, "Analysis
of the photon indistinguishability in incoherently excited
quantum dots", Phys. Rev. B 73, 35316 (2006).
 F. Troiani, M. Affronte, S. Carretta, P. Santini,
and G. Amoretti, "Proposal for quantum gates in permanently
coupled antiferromagnetic spin rings without need of local
fields", Phys. Rev. Lett. 94, 190501 (2005).
 F. Troiani, A. Ghirri, M. Affronte, S. Carretta,
P. Santini, G. Amoretti, S. Piligkos, G. Timco, and rue>
R. E. P. Winpenny, "Molecular engineering of antiferromagnetic
molecular rings for quantum computation", Phys. Rev. Lett.
94, 207208 (2005).
 D. Bellucci, F. Troiani, G. Goldoni, and E. Molinari,
"Neutral and charged electronhole complexes in artificial
molecules: Quantum transitions induced by the inplane magnetic
field", Phys. Rev. B 70, 205332 (2004).
 A. Bertoni, M. Rontani, G. Goldoni, F. Troiani,
and E. Molinari, "Fieldcontrolled suppression of phononinduced
transitions in coupled quantum dots", Appl. Phys. Lett.
85, 4729 (2004).
 D. Bellucci, M. Rontani, F. Troiani, G. Goldoni,
and E. Molinari, "Competing mechanisms for singlettriplet
transition in artificial molecules", Phys. Rev. B 69, RC
201308 (2004).
 F. Troiani, "Tunneling and ElectricField Effects
on ElectronHole Localization in Artificial Molecules",
Solid State Comm. 128, 147 (2003).
 F. Troiani, E. Molinari, and U. Hohenester, "Highfinesse
optical quantum gates for electron spins in artificial molecules",
Phys.
 M. Lomascolo, A.Vergine, T.K. Johal, R. Rinaldi, A. Passaseo,
R. Cingolani, S. Patanč, M. Lombardi, M. Allegrini, F.
Troiani, and E. Molinari, "Dominance of charged excitons
in single quantum dot photoluminescence spectra", Phys.
Rev. B 66, RC 41302 (2002).
 F. Troiani, U. Hohenester, and E. Molinari, "Electronhole
localization in coupled quantum dots", Phys. Rev. B 65,
RC 161301 (2002).
 M. Rontani, F. Troiani, U. Hohenester, and E. Molinari,
"Quantum phases in artificial molecules", Solid State Commun.
119, 309 (2001) Invited paper in Special Issue on Spin Effects
in Mesoscopic Systems.
 U. Hohenester, F. Troiani, E. Molinari, G. Panzarini,
and C. Machiavello, "Coherent population transfer in coupled
semiconductor quantum dots", Appl. Phys. Lett. 77, 1864
(2000).
 F. Troiani, U. Hohenester, and E. Molinari, "Exploiting
excitonexciton interactions in semiconductor quantum dot
for quantuminformation processing", Phys. Rev. B 62, RC
2263 (2000).
REVIEW ARTICLES AND BOOK CHAPTERS
 F. Troiani, I. WilsonRae, and C. Tejedor, "Optical readout
of singlecarrier spin in semiconductor quantum dots", in Semiconductor
Quantum Bits, edito da Pan Stanford Publishing / World Scientific Publishing
(2007), in press.
 F. Troiani, U. Hohenester, E. Molinari, I. D'Amico, and F.
Rossi, "Fewparticle effects in semiconductor macroatoms/molecules" (Ch. 5),
in Semiconductor macroatoms: basic physics and quantumdevice applications,
edited by Imperial College Press / World Scientific Publishing (2006).
 I. D'Amico, and F. Rossi, F. Troiani, U. Hohenester,
"Alloptical schemes for quantuminformation processing with semiconductor
macroatoms" (Ch. 8), in Semiconductor macroatoms: basic physics and
quantumdevice applications, edited by Imperial College Press / World
Scientific Publishing (2006).
 U. Hohenester, F. Troiani, and E. Molinari, "Optically induced
coherence effects in artificial atoms and molecules", in RadiationMatter
Interaction in Confined Systems, edited by L.C. Andreani, G. Benedek, and E.
Molinari (Italian Physics Society, Bologna, 2002), p. 25.
OTHER PUBLICATIONS ON REFEREED JOURNALS
 E. del Valle, F. Laussy, F. Troiani, and C. Tejedor , "Steady
state of two quantum dots in a cavity", Superlattices and Microstructures,
in press.
 E. del Valle, F. Troiani, and C. Tejedor, "Cavity
electrodynamics with two quantum dots", Proc. 28th International Conference
on the Physics of Semiconductors (Vienna, 2006), in press.
 M. Affronte, F. Troiani, A. Ghirri, A. Candini, M.
Evangelisti, V. Corradini, S. Carretta, P. Santini, G. Amoretti, F. Tuna, G.
Timco and R. E. P. Winpenny, "Single molecule magnets for quantum
computation", J. Phys. D: Appl. Phys., in press.
 M. Affronte, F. Troiani, A. Ghirri, A. Candini, M.
Evangelisti, V. Corradini, S. Carretta, P. Santini, G. Timco , R.E.P.
Winpenny, "Molecular Spin Clusters for Quantum Computation", J. Magnetism &
Magnetic Materials 310, 14601461 (2007).
 M. Affronte, F. Troiani, A. Ghirri, A. Candini, M.
Evangelisti, S. Carretta, P. Santini, G. Amoretti, S. Piligkos, G. Timco and
R. E. P. Winpenny, "Antiferromagnetic molecular rings for quantum
computation", Polyhedron 24 2562 (2005).
 D. Bellucci, F. Troiani, G. Goldoni, and E. Molinari,
"Magneticfield dependent optical properties and interdot correlations in
artificial molecules", J. Lumin. 112, 109 (2005).
 D. Bellucci, F. Troiani, G. Goldoni, and E. Molinari
"Biexcitons in artificial molecules with inplane magnetic field", Physica E
26, 308 (2005).
 D. Bellucci, M. Rontani, G. Goldoni, F. Troiani, and E.
Molinari "Interacting electrons in artificial molecules with magnetic field
of arbitrary direction", Physica E 26, 327 (2005).
 A. Bertoni, M. Rontani, G. Goldoni, F. Troiani, E. Molinari,
"Suppression of acusticphononinduced electron transitions in coupled
quantum dots", Physica E 26, 427 (2005).
 G. Goldoni, F. Troiani, M. Rontani, D. Bellucci, E. Molinari,
and U. Hohenester, "Collective properties of electrons and holes in coupled
quantum dots", Proc. NATO Series II 190, edito da B. Joyce, P. Kelires, A.
Naumovets, and D.D. Vvedensky (2005).
 F. Troiani, U. Hohenester, and E. Molinari, "Highfinesse
optical quantum gates for electron spins in artificial molecules", Physica E
21, 1061 (2004).
 D. Bellucci, M. Rontani, G. Goldoni, F. Troiani, and E.
Molinari, "SpinSpin Interaction In Artificial Molecules With InPlane
Magnetic Field", to appear in Physica E (2004).
 U. Hohenester, F. Troiani, and E. Molinari, "Fewparticle
states and quantuminformation processing in quantum dots", Proc. 25th
International Conference on the Physics of Semiconductors (Osaka 2000),
edited by N. Miura and T. Ando, Springer Berlin (2001).
 F. Troiani, U. Hohenester, and E. Molinari,
"Quantuminformation processing in semiconductor quantum dots", phys. stat.
sol. (b) 224, 849 (2001)
