23,936 research outputs found
Dynamics of the quantum Duffing oscillator in the driving induced bistable regime
We investigate the nonlinear response of an anharmonic monostable quantum
mechanical resonator to strong external periodic driving. The driving thereby
induces an effective bistability in which resonant tunneling can be identified.
Within the framework of a Floquet analysis, an effective Floquet-Born-Markovian
master equation with time-independent coefficients can be established which can
be solved straightforwardly. Various effects including resonant tunneling and
multi-photon transitions will be described. Our model finds applications in
nano-electromechanical devices such as vibrating suspended nano-wires as well
as in non-destructive read-out procedures for superconducting quantum bits
involving the nonlinear response of the read-out SQUID.Comment: 21 pages, 11 figure
Solid-state quantum optics with quantum dots in photonic nanostructures
Quantum nanophotonics has become a new research frontier where quantum optics
is combined with nanophotonics in order to enhance and control the interaction
between strongly confined light and quantum emitters. Such progress provides a
promising pathway towards quantum-information processing on an all-solid-state
platform. Here we review recent progress on experiments with single quantum
dots in nanophotonic structures. Embedding the quantum dots in photonic
band-gap structures offers a way of controlling spontaneous emission of single
photons to a degree that is determined by the local light-matter coupling
strength. Introducing defects in photonic crystals implies new functionalities.
For instance, efficient and strongly confined cavities can be constructed
enabling cavity-quantum-electrodynamics experiments. Furthermore, the speed of
light can be tailored in a photonic-crystal waveguide forming the basis for
highly efficient single-photon sources where the photons are channeled into the
slowly propagating mode of the waveguide. Finally, we will discuss some of the
surprises that arise in solid-state implementations of quantum-optics
experiments in comparison to their atomic counterparts. In particular, it will
be shown that the celebrated point-dipole description of light-matter
interaction can break down when quantum dots are coupled to plasmon
nanostructures.Comment: Review. 15 pages, 9 figure
Standing Swells Surveyed Showing Surprisingly Stable Solutions for the Lorenz '96 Model
The Lorenz '96 model is an adjustable dimension system of ODEs exhibiting
chaotic behavior representative of dynamics observed in the Earth's atmosphere.
In the present study, we characterize statistical properties of the chaotic
dynamics while varying the degrees of freedom and the forcing. Tuning the
dimensionality of the system, we find regions of parameter space with
surprising stability in the form of standing waves traveling amongst the slow
oscillators. The boundaries of these stable regions fluctuate regularly with
the number of slow oscillators. These results demonstrate hidden order in the
Lorenz '96 system, strengthening the evidence for its role as a hallmark
representative of nonlinear dynamical behavior.Comment: 10 pages, 8 figure
Swift heat transfer by fast-forward driving in open quantum systems
Typically, time-dependent thermodynamic protocols need to run asymptotically
slowly in order to avoid dissipative losses. By adapting ideas from
counter-diabatic driving and Floquet engineering to open systems, we develop
fast-forward protocols for swiftly thermalizing a system oscillator locally
coupled to an optical phonon bath. These protocols control the system frequency
and the system-bath coupling to induce a resonant state exchange between the
system and the bath. We apply the fast-forward protocols to realize a fast
approximate Otto engine operating at high power near the Carnot Efficiency. Our
results suggest design principles for swift cooling protocols in coupled
many-body systems.Comment: 16 pages, 10 figure
Resonant symmetry lifting in a parametrically modulated oscillator
We study a parametrically modulated oscillator that has two stable states of
vibrations at half the modulation frequency . Fluctuations of the
oscillator lead to interstate switching. A comparatively weak additional field
can strongly affect the switching rates, because it changes the switching
activation energies. The change is linear in the field amplitude. When the
additional field frequency is , the field makes the
populations of the vibrational states different thus lifting the states
symmetry. If differs from , the field modulates the
state populations at the difference frequency, leading to fluctuation-mediated
wave mixing. For an underdamped oscillator, the change of the activation energy
displays characteristic resonant peaks as a function of frequency
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