Two-dimensional spectroscopy is an emerging topic in the field of spectroscopy. By mapping correlations of two spectroscopic measurements, two-dimensional spectroscopy resolves complexity buried in the signal from complex and/or fluctuating molecular systems. We first outline the basic concepts of two-dimensional spectroscopy and then discuss a new single-molecule based method, two-dimensional fluorescence lifetime correlation spectroscopy, which visualizes microsecond protein dynamics.
We prove a general trade-off relation between heat current and dissipation, which implies that no heat engine with non-vanishing power can attain the maximum Carnot efficiency. The conclusion applies to any heat engine described by a classical Markov process.
We recently developed a new variational method named “tensor-optimized antisymmetrized molecular dynamics”(TOAMD) for nuclear many-body systems. We can treat the bare nucleon-nucleon interaction in terms of the correlation functions for the short-range repulsion in the central force and for the non-central tensor force. We can extend the variational space of TOAMD by adding the correlation terms successively in the form of the power series expansion. It is shown that TOAMD reproduces the results of the few-body calculations for light nuclei. It is confirmed that the variational accuracy of TOAMD is better than that of the variational Monte Carlo calculation based on the Jastrow correlation method.
We theoretically study current-induced orbital magnetization in a chiral crystal, an orbital version of the Edelstein effect, using a simple tight-binding model of helical crystals. The induced magnetizations are opposite for right-handed and left-handed helices. We propose an analogy between the current-induced orbital magnetization and an Ampere field in a solenoid in classical electrodynamics. In order to quantify this effect, we define a dimensionless parameter from the response coefficient relating a current density with an orbital magnetization. This dimensionless parameter can be regarded as a number of turns within a unit cell when the crystal is regarded as a solenoid, and it represents how “chiral” the crystal is. We show that a Weyl semimetal with all the Weyl nodes close to the Fermi energy can have a large value of this dimensionless parameter, which can exceed that of a classical solenoid.