Question: The first person to interpret Relational quantum mechanics has worked in what countries? 

<P0-S0>  His work is mainly in the field of quantum gravity, where he is among the founders of the loop quantum gravity theory. <P0-S1>  He has also worked in the history and philosophy of science. <P0-S2> Carlo Rovelli (born 3 May 1956) is an Italian theoretical physicist and writer who has worked in Italy, the United States and since 2000, in France. <P0-S3>  He collaborates regularly with several Italian newspapers, in particular the cultural supplements of "Il Corriere della Sera", "Il Sole 24 Ore" and "La Repubblica". <SEP> <P1-S0> Quantum chaos is a branch of physics which studies how chaotic classical dynamical systems can be described in terms of quantum theory. <P1-S1>  The primary question that quantum chaos seeks to answer is: "What is the relationship between quantum mechanics and classical chaos?" <P1-S2>  The correspondence principle states that classical mechanics is the classical limit of quantum mechanics. <P1-S3>  If this is true, then there must be quantum mechanisms underlying classical chaos (although this may not be a fruitful way of examining classical chaos). <P1-S4>  If quantum mechanics does not demonstrate an exponential sensitivity to initial conditions, how can exponential sensitivity to initial conditions arise in classical chaos, which must be the correspondence principle limit of quantum mechanics? <P1-S5>  In seeking to address the basic question of quantum chaos, several approaches have been employed: <SEP> <P2-S0> Relational quantum mechanics (RQM) is an interpretation of quantum mechanics which treats the state of a quantum system as being observer-dependent, that is, the state "is" the relation between the observer and the system. <P2-S1>  It is inspired by the key idea behind special relativity, that the details of an observation depend on the reference frame of the observer, and uses some ideas from Wheeler on quantum information. <P2-S2>  This interpretation was first delineated by Carlo Rovelli in a 1994 preprint, and has since been expanded upon by a number of theorists. <SEP> <P3-S0> The relational approach to quantum physics is an alternative approach to and interpretation of quantum mechanics. <P3-S1>  It asserts that the physical world can only be studied accurately in terms of "relationships" between systems, as all experimentally verifiable facts about the world result explicitly from interactions (such as the interaction between a light field and a detector). <P3-S2>  According to the relational approach, the assumption that objects possess absolute properties (such as an absolute particle, independent of any detection frame) inevitably leads to ambiguities and paradoxes when these objects are studied closely. <P3-S3>  The approach was adopted, in a time span of 1992-1996, by Q. Zheng, S. Hughes, and T. Kobayashi in the University of Tokyo. <P3-S4>  As early as in 1985, S. Kochen suggested that the paradoxes of quantum physics could be overcome by developing a relational approach, which was needed at one time to solve the paradoxes of relativistic physics of space and time. <P3-S5>  It is also hoped that this entry will serve as a complement to Rovelli’s relational quantum mechanics (RQM).