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In this paper recent substantial progress in applying the density-matrix renormalizationgroup (DMRG) to the simulation of the time-evolution of strongly correlated quantum systems in one dimension is reviewed. Various approaches to generating a time-evolution numerically are considered. The key focus of this review is on current strategies to circumvent the limitations of the quite small subspace well approximated by DMRG, by either enlarging or changing it as time evolves. All these approaches can be extended to the simulation of mixed, i.e. finitetemperature states. While this paper is phrased almost entirely in standard DMRG language, I finish by considering the alternative formulation of time-evolutions in the language of matrix product states which is less well-known but conceptually more powerful.KEYWORDS: density-matrix renormalization-group, strongly correlated systems, quantum information theory IntroductionMore than ten years after the invention of the Density-Matrix Renormalization Group (DMRG) by Steve White, 1, 2 this method has become the method of choice for the numerical simulation of the equilibrium properties of strongly correlated one-dimensional quantum systems.3, 4 Ground-state properties of both bosonic and fermionic systems have been calculated often at almost machine precision and comparatively low computational cost. While these results have been of prime importance in understanding the details of gapped Haldane systems or critical Luttinger liquids, to name but a few applications, for a long time hardly any attention had been paid to the time-evolution of strongly correlated quantum systems, both due to the comparative lack of experimental input in the past and to the inherent difficulties of actually calculating such time-evolutions. The last years have seen an increasing number of experimental results on non-trivial time-evolutions. Perhaps most spectacular was the recent mastery of storing ultracold bosonic atoms in a magnetic trap superimposed by an optical lattice: This has allowed to drive these atoms, at will, by time-dependent variations of the optical lattice strength, from the superfluid (metallic) to the Mott insulating regime. These regimes are linked by one of the key phase transitions in strongly correlated systems.5 Quite generally, progress in the fields of nanoelectronics and spintronics raises the question how (strongly correlated) quantum many-body systems react to external timedependent perturbations and how transport can be calculated quantitatively also far from the linear-response regime. On the computational physicists' side, the last twelve months or so have seen an extraordinary surge of activity in developing DMRG variants applicable to timeevolutions, such that by now we have various very powerful and conceptually innovative DMRG algorithms for pure as well as mixed quantum states, for non-dissipative as well as dissipative dynamics.The relationship between these various algorithms is

The human body literally glimmers. The intensity of the light emitted by the body is 1000 times lower than the sensitivity of our naked eyes. Ultraweak photon emission is known as the energy released as light through the changes in energy metabolism. We successfully imaged the diurnal change of this ultraweak photon emission with an improved highly sensitive imaging system using cryogenic charge-coupled device (CCD) camera. We found that the human body directly and rhythmically emits light. The diurnal changes in photon emission might be linked to changes in energy metabolism.

The lattice specific heat C lat of La-based filled skutterudites LaT 4 X 12 (T = Fe, Ru and Os; X = P, As and Sb) has been systematically studied, and both the Debye temperature Θ D and the Einstein temperature Θ E of LaT 4 X 12 were carefully estimated. We confirmed that a correlation exists between Θ D and the reciprocal of the square root of average atomic mass for LaT 4 P 12 , LaT 4 As 12 , and LaT 4 Sb 12 . The Θ D of filled skutterudites was found to depend mainly on the nature of the species X forming the cage. The temperature dependence of C lat /T 3 for LaT 4 X 12 exhibited a large broad maximum at low temperatures (10 -30 K), which suggests a nearly dispersionless low-energy optical mode characterized by Einstein specific heat. Since no such broad maximum exists for the unfilled skutterudite RhP 3 , the low-energy optical modes are associated with vibration involving La ions in the X 12 cage (the so-called "guest ion modes"). The Θ E of filled skutterudites was found to roughly correspond to the energy of low-energy guest ion optical modes. Furthermore, a good correlation was shown to exist between Θ E and r R−X − r R3+ , where r R−X is the R-X distance and r R3+ is the effective ionic radius of R 3+ . As r R−X − r R3+ increased, Θ E was found to decrease.