The science of the WG 1    For a theoretical physicist, the concept of black hole may be intuitively associated to the Einstein field equations and the curvature of spacetime. In the mind of an astronomer, a black hole may instead recall the fate of very massive stars, the complex trajectories that an invisible attractor imposes on stars close to the center of the Milky Way or the monstrous engine that powers the core of active galaxies. Someone who is not very familiar with physics may think of black holes simply as a concentration of matter so dense that not even light can escape it. Depending on our cultural background, the first image that the concept of black holes brings to our mind may differ considerably, but most of us would surely agree on indicating the dark abyss of deep space as the natural habitat of these creatures. This conclusion, however, may be wrong. In scientist's hopes, the 27-kilometer circumference tunnel of the Large Hadronic Collider (LHC, currently the largest and most powerful particle accelerator in the world) may become another natural location for the birth and death of black holes.    According to theory, nothing hinders the existence of black holes on extremely small size scales. We could create a black hole with a Schwarzschild radius of 1mm if we were able to confine a mass of ~ 1024 kg (about ten times the mass of the Moon) within a volume of a pinhead; but this goes far beyond our capabilities. The creation of black holes is hampered by technological limits. Going toward smaller mass scales may ease the problem (the smaller the mass, the less difficult to compress it to extreme densities), but there is a theoretical lower limit that cannot be overcome, known as the Planck mass (mP ~ 10-8 kg). The experimental creation of black holes implies the concentration of a mass larger than mP within subnuclear length scales.    The largest concentration of energy (and therefore of mass, remembering Einstein's famous E=mc2) that our technology can achieve is given by the collision of accelerated particles within facilities like the LHC. At present, LHC is able to collide particles at energies up to 3.5 TeV, corresponding to a mass of ~ 10-23 kg. At full power, in 2014, the maximum energy released by the collisions should increase to ~ 7 TeV ___ about 15 orders of magnitude below the Planck mass! Does it mean that we have absolutely no chance to create a black hole? Yes and no. Yes ___ if the universe in which we live is simply 4-dimensional (note ___ also time counts as a dimension). But, on very small length scales, quantum eects are predominant, and the universe may appear radically different from how we perceive it. According to some theories, it may be described best by hypothesizing more than 4 dimensions. In this case, the energy required for the creation of a quantum black hole may be considerably lower than we expected in the first place ___ maybe as low as a few TeV ___ and, among the products of the collision of very energetic particles, we may observe a black hole. Or, more precisely, the remnants it leaves behind after its death ___ our most advanced detectors would not be able to directly see a quantum black hole because, according to Hawking's theory, it would immediately evaporate after its creation.    The study of quantum black holes is deeply connected with some of the most fundamental questions concerning particle physics, quantum theories and general relativity ___ the three milestones of XX century physics. This may help to understand its importance in shaping the theories of the physics to come.