text: 313,246,1369596736054976514,471165766,Ion Errea,"Today it is an important day in my research career: we release the SSCHA code. You can find the info about the code here (<LINK>), read the paper related to the code in <LINK>, and follow it on twitter @SSCHA_code All this started when in my PhD Bruno Rousseau proposed to use the Self-Consistent Harmonic Approximation to study the high-pressure simple cubic phase of Ca. We implemented the idea, but the implementation was too primordial for any other material <LINK> As a postdoc I moved to Paris to work Francesco Mauri’s group. We developed there the SSCHA and started its first applications on hydrogen-based superconductors <LINK> <LINK> Later Raffaello Bianco showed how the SSCHA theory could be expanded to predict second-order phase transitions easily and describe phonon spectral properties <LINK> These improvements have been crucial to study CDW phase transitions and perform thermal transport calculations on thermoelectric materials <LINK> <LINK> Now @mesonepi has taken the lead in the development of the code and brought to it an improved efficiency and the possibility of making structural relaxations in the quantum energy landscape <LINK> The latter development was crucial to show how quantum effects make stable the high-temperature superconducting LaH10 <LINK> Now the code is distributed as open source, available to everybody. Your contributions will be welcome and surely will improve the capacity of the code.",https://arxiv.org/abs/2103.03973,"The efficient and accurate calculation of how ionic quantum and thermal fluctuations impact the free energy of a crystal, its atomic structure, and phonon spectrum is one of the main challenges of solid state physics, especially when strong anharmonicy invalidates any perturbative approach. To tackle this problem, we present the implementation on a modular Python code of the stochastic self-consistent harmonic approximation method. This technique rigorously describes the full thermodyamics of crystals accounting for nuclear quantum and thermal anharmonic fluctuations. The approach requires the evaluation of the Born-Oppenheimer energy, as well as its derivatives with respect to ionic positions (forces) and cell parameters (stress tensor) in supercells, which can be provided, for instance, by first principles density-functional-theory codes. The method performs crystal geometry relaxation on the quantum free energy landscape, optimizing the free energy with respect to all degrees of freedom of the crystal structure. It can be used to determine the phase diagram of any crystal at finite temperature. It enables the calculation of phase boundaries for both first-order and second-order phase transitions from the Hessian of the free energy. Finally, the code can also compute the anharmonic phonon spectra, including the phonon linewidths, as well as phonon spectral functions. We review the theoretical framework of the stochastic self-consistent harmonic approximation and its dynamical extension, making particular emphasis on the physical interpretation of the variables present in the theory that can enlighten the comparison with any other anharmonic theory. A modular and flexible Python environment is used for the implementation, which allows for a clean interaction with other packages. We briefly present a toy-model calculation to illustrate the potential of the code. ","The Stochastic Self-Consistent Harmonic Approximation: Calculating