A5081619200- Quantum and electron transport phenomena
- Semiconductor Quantum Structures and Devices
- Magnetism in coordination complexes
- Quantum Information and Cryptography
- Molecular Junctions and Nanostructures
- Spectroscopy and Quantum Chemical Studies
- Advanced NMR Techniques and Applications
- Organic and Molecular Conductors Research
- Electron Spin Resonance Studies
- Quantum many-body systems
- Porphyrin and Phthalocyanine Chemistry
- Quantum optics and atomic interactions
- Physics of Superconductivity and Magnetism
- Advanced Chemical Physics Studies
- Semiconductor materials and devices
- Advancements in Semiconductor Devices and Circuit Design
- Lanthanide and Transition Metal Complexes
- Quantum Computing Algorithms and Architecture
- Surface and Thin Film Phenomena
- Atomic and Subatomic Physics Research
- Mechanical and Optical Resonators
- Quantum Dots Synthesis And Properties
- Crystallization and Solubility Studies
- X-ray Diffraction in Crystallography
- Photochemistry and Electron Transfer Studies
Istituto Nanoscienze
2016-2025
University of Modena and Reggio Emilia
2001-2023
Sapienza University of Rome
2016
Casa di Cura San Michele
2015
Azienda Unita' Sanitaria Locale Di Modena
2015
Istituto Nazionale per la Fisica della Materia
2000-2008
Universidad Autónoma de Madrid
2006-2007
Istituto Nazionale di Fisica Nucleare, Centro Nazionale Analisi Fotogrammi
2006
Abstract The optical excitation of organic semiconductors not only generates charge-neutral electron-hole pairs (excitons), but also charge-separated polaron with high yield. microscopic mechanisms underlying this charge separation have been debated for many years. Here we use ultrafast two-dimensional electronic spectroscopy to study the dynamics pair formation in a prototypical polymer thin film on sub-20-fs time scale. We observe multi-period peak oscillations persisting up about 1 ps as...
The substitution of one metal ion in a Cr-based molecular ring with dominant antiferromagnetic couplings allows to engineer its level structure and ground-state degeneracy. Here we characterize Cr7Ni by means low-temperature specific-heat torque-magnetometry measurements, thus determining the microscopic parameters corresponding spin Hamiltonian. energy spectrum suppression leakage-inducing S-mixing render molecule suitable candidate for qubit implementation, as further substantiated our...
We study the triangular antiferromagnet ${\mathrm{Cu}}_{3}$ in external electric fields, using symmetry group arguments and a Hubbard model approach. identify spin-electric coupling caused by an interplay between spin exchange, spin-orbit interaction, chirality of underlying texture molecular magnet. This allows for control (qubit) states, e.g., STM tip or microwave cavity. propose experimental test identifying magnets exhibiting effects.
We propose an all-optical implementation of quantum-information processing in semiconductor quantum dots, where electron-hole excitations (excitons) serve as the computational degrees freedom (qubits). show that strong dot confinement leads to overall enhancement Coulomb correlations and a renormalization excitonic states, which can be exploited for performing conditional unconditional qubit operations.
We propose a scheme for the implementation of quantum gates which is based on qubit encoding in antiferromagnetic molecular rings. show that proper engineering intercluster link would result an effective coupling vanishes as far system kept computational space, while it turned by selective excitation specific auxiliary states. These are also shown to allow performing single-qubit and two-qubit without individual addressing rings means local magnetic fields.
We present recent achievements and perspectives for the encoding of qubits with molecular spin clusters.
We characterize supramolecular magnetic structures, consisting of two weakly coupled antiferromagnetic rings, by low-temperature specific heat, susceptibility, magnetization and electron paramagnetic resonance measurements. Intra- inter-ring interactions are modeled through a microscopic spin-Hamiltonian approach that reproduces all the experimental data quantitatively legitimates use an effective two-qubit picture. Spin entanglement between rings is experimentally demonstrated...
Molecular nanomagnets show clear signatures of coherent behavior and have a wide variety effective low-energy spin Hamiltonians suitable for encoding qubits implementing spin-based quantum information processing. At the nanoscale, preferred mechanism control systems is through application electric fields, which are strong, can be locally applied, rapidly switched. In this work, we provide theoretical tools search single molecule magnets control. By group-theoretical symmetry analysis find...
Quantum simulators are controllable systems that can be used to simulate other quantum systems. Here we focus on the dynamics of a chain molecular qubits with interposed antiferromagnetic dimers. We theoretically show its controlled by means uniform magnetic pulses and mimic evolution systems, including fermionic ones. propose two proof-of-principle experiments based simulation Ising model in transverse field tunneling magnetization spin-1 system.
A doped semiconductor double-quantum-dot molecule is proposed as a qubit realization. The quantum information encoded in the electron spin, thus benefiting from long relevant decoherence times; enhanced flexibility of molecular structure allows one to map spin degrees freedom onto orbital ones and vice versa opens possibility for high-finesse (conditional unconditional) gates by means stimulated Raman adiabatic passages.
We experimentally and theoretically investigate the photoluminescence broadening of different excitonic complexes in single self-assembled GaAs∕AlGaAs quantum dots. demonstrate that fine-structure splitting leads to a sizable line whenever detection is not resolved polarization. The residual polarized measurements systematically larger for exciton with respect both trion biexciton recombination. experimental data agree calculations confined Stark effect induced by charge defects dot (QD)...
We show that isosceles antiferromagnetic spin triangles constitute simple and very advantageous units for implementing quantum gates with magnetic molecules. Indeed, the structure of their low-energy wave functions enables switchable effective interqubit couplings even in presence permanent microscopic interactions. The great advantage proposed hardware is no fine tuning intermolecular interactions required. This significantly increases robustness respect to disorder both local global...
We report on real molecular complexes and propose strategies that explore the possibility of implementation specific quantum computation architectures with spin systems. focus Cr3+ carboxylate derivatives use Loss-DiVincenzo scheme as reference.
The problem of coupling multiple spin ensembles through cavity photons is revisited by using (3,5-dichloro-4-pyridyl)bis(2,4,6-trichlorophenyl)methyl (PyBTM) organic radicals and a high-${T}_{c}$ superconducting coplanar resonator. An exceptionally strong obtained up to three are simultaneously coupled. made physically distinguishable chemically varying the $g$ factor exploiting inhomogeneities applied magnetic field. coherent mixing field modes demonstrated observed anticrossing, along with...
Phenomena involving electron transfer are ubiquitous in nature, photosynthesis and enzymes or protein activity being prominent examples. Their deep understanding thus represents a mandatory scientific goal. Moreover, controlling the separation of photogenerated charges is crucial prerequisite many applicative contexts, including quantum electronics, photo-electrochemical water splitting, photocatalytic dye degradation, energy conversion. In particular, photoinduced charge pivotal step...
Internal conversion (IC) is a common radiationless transition in polyatomic molecules. Theory predicts that molecular vibrations assist IC between excited states, and ultrafast experiments can provide insight into their structure–function relationship. Here we elucidate the dynamics of vibrational modes driving process within Q band functionalized porphyrin molecule. Through combination multidimensional spectroscopies theoretical modeling, observe 60 fs Qy–Qx demonstrate it driven by...
We compute the concurrence of polarization-entangled photon pairs generated by biexciton cascade decay a semiconductor quantum dot. show how cavity-induced increase emission rate reduces effect dot dephasing and excitonic fine structure on concurrence. However, strong dot-cavity couplings, as well low detection efficiencies, detrimental multiple cascades. This affects merits entangled photon-pair source, beyond what is estimated tomography.
We investigate hyperfine-induced decoherence in a triangular spin-cluster for different qubit encodings. Electrically controllable eigenstates of spin chirality (C_z) show times that approach milliseconds, two orders magnitude longer than those estimated the total projection (S_z) and partial sum (S_{12}). The robustness is due to its decoupling from both total- individual-spin components cluster. This results suppression effective interaction between C_z nuclear bath.
Future applications of molecular units in quantum information technologies require a fine control at the single molecule level.
Learning the art of exploiting interplay between different units at atomic scale is a fundamental step in realization functional nano-architectures and interfaces. In this context, understanding controlling magnetic coupling molecular centers their environment still challenging task. Here we present combined experimental-theoretical work on prototypical case bis(phthalocyaninato)-lanthanide(III) (LnPc2) nanomagnets magnetically coupled to Ni substrate. By means X-ray circular dichroism show...
Electric fields represent an ideal means for controlling spins at the nanoscale and, more specifically, manipulating protected degrees of freedom in multispin systems. Here we perform low-temperature magnetic far-IR spectroscopy on a molecular spin triangle (Fe3) and provide initial experimental evidence suggesting spin-electric transitions polynuclear complexes. The co-presence electric- magnetic-dipole transitions, allows us to estimate coupling. Based Hamiltonian simulations spectra,...