اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدDirect Energy Transfer in Systems of Polymerized Acceptors
49
0
0.0
(
0
)
اسأل ChatGPT حول البحث
ﻻ يوجد ملخص باللغة العربية
We study the direct incoherent energy transfer from an immobile excited donor molecule to acceptor molecules, which are all attached to polymer chains, randomly arranged in a viscous solvent. The decay forms are found explicitly, in terms of an optimal-fluctuation method, for arbitrary conformations of polymers.
قيم البحث
اقرأ أيضاً
Energy dissipation is an unavoidable phenomenon of physical systems that are directly coupled to an external environmental bath. The ability to engineer the processes responsible for dissipation and coupling is fundamental to manipulate the state of
such systems. This is particularly important in oscillatory states whose dynamic response is used for many applications, e.g. micro and nano-mechanical resonators or sensing and timing, qubits for quantum engineering, and vibrational modes for optomechanical devices. In situations where stable oscillations are required, the energy dissipated by the vibrational modes is usually compensated by replenishment from external energy sources. Consequently, if the external energy supply is removed, the amplitude of oscillations start to decay immediately, since there is no means to restitute the energy dissipated. Here, we demonstrate a novel strategy to maintain stable oscillations, i.e. with constant amplitude and frequency, without supplying external energy to compensate losses. The fundamental intrinsic mechanism of mode coupling is used to redistribute and store mechanical energy among vibrational modes and coherently transfer it back to the principal mode when the external excitation is off. To experimentally demonstrate this phenomenon that defies physical intuition, we exploit the nonlinear dynamic response of microelectromechanical (MEMS) oscillators to couple two different vibrational modes through an internal resonance. Since the underlying mechanism describing the fundamentals of this new phenomenon is generic and representative of a large variety of systems, the presented method provides a new dissipation engineering strategy that would enable a new generation of autonomous devices.
We study the energy transfer in the linear system $$ begin{cases} ddot u+u+dot u=bdot v ddot v+v-epsilon dot v=-bdot u end{cases} $$ made by two coupled differential equations, the first one dissipative and the second one antidissipative. We see how
the competition between the damping and the antidamping mechanisms affect the whole system, depending on the coupling parameter $b$.
Excitons, composite electron-hole quasiparticles, are known to play an important role in optoelectronic phenomena in many semiconducting materials. Recent experiments and theory indicate that the band-gap optics of the newly discovered monolayer tran
sition-metal dichalcogenides (TMDs) is dominated by tightly bound valley excitons. The strong interaction of excitons with long-range electromagnetic fields in these 2D systems can significantly affect their intrinsic properties. Here, we develop a semi-classical framework for intrinsic exciton-polaritons in monolayer TMDs that treats their dispersion and radiative decay on the same footing and can incorporate effects of the dielectric environment. It is demonstrated how both inter- and intra-valley long-range interactions influence the dispersion and decay of the polaritonic eigenstates. We also show that exciton-polaritons can be efficiently excited via resonance energy transfer from quantum emitters such as quantum dots, which may be useful for various applications.
We consider the fracture of a free-standing two-dimensional (2D) elastic-brittle network to be used as protective coating subject to constant tensile stress applied on its rim. Using a Molecular Dynamics simulation with Langevin thermostat, we invest
igate the scission and recombination of bonds, and the formation of cracks in the 2D graphene-like hexagonal sheet for different pulling force $f$ and temperature $T$. We find that bond rupture occurs almost always at the sheet periphery and the First Mean Breakage Time $<tau>$ of bonds decays with membrane size as $<tau> propto N^{-beta}$ where $beta approx 0.50pm 0.03$ and $N$ denotes the number of atoms in the membrane. The probability distribution of bond scission times $t$ is given by a Poisson function $W(t) propto t^{1/3} exp (-t / <tau>)$. The mean failure time $<tau_r>$ that takes to rip-off the sheet declines with growing size $N$ as a power law $<tau_r> propto N^{-phi(f)}$. We also find $<tau_r> propto exp(Delta U_0/k_BT)$ where the nucleation barrier for crack formation $Delta U_0 propto f^{-2}$, in agreement with Griffiths theory. $<tau_r>$ displays an Arrhenian dependence of $<tau_r>$ on temperature $T$. Our results indicate a rapid increase in crack spreading velocity with growing external tension $f$.
We investigate the ground state magnetization plateaus appearing in spin 1/2 polymerized Heisenberg chains under external magnetic fields. The associated fractional quantization scenario and the exponents which characterize the opening of gapful exci
tations are analyzed by means of abelian bosonization methods. Our conclusions are fully supported by the extrapolated results obtained from Lanczos diagonalizations of finite systems.
سجل دخول لتتمكن من نشر تعليقات
التعليقات
جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
