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Multiple energy scales are detected in measurements of the thermodynamic and transport properties in heavy fermion metals. We demonstrate that the experimental data on the energy scales can be well described by the scaling behavior of the effective mass at the fermion condensation quantum phase transition, and show that the dependence of the effective mass on temperature and applied magnetic fields gives rise to the non-Fermi liquid behavior. Our analysis is placed in the context of recent salient experimental results. Our calculations of the non-Fermi liquid behavior, of the scales and thermodynamic and transport properties are in good agreement with the heat capacity, magnetization, longitudinal magnetoresistance and magnetic entropy obtained in remarkable measurements on the heavy fermion metal YbRh2Si2.Comment: 8 pages, 8 figure

Experimental studies of the antiferromagnetic (AF) heavy fermion metal YbRh2Si2 in a magnetic field B indicate the presence of a jump in the Hall coefficient at a magnetic-field tuned quantum state in the zero temperature limit. This quantum state occurs at B ≥ Bc0 and induces the jump even though the change of the magnetic field at B = Bc0 is infinitesimal. We investigate this by using the model of heavy electron liquid with the fermion condensate. Within this model the jump takes place when the magnetic field reaches the critical value Bc0 at which the ordering temperature TN (B = Bc0) of the AF transition vanishes. We show that at B → Bc0, this second order AF phase transition becomes the first order one, making the corresponding quantum and thermal critical fluctuations vanish at the jump. At T → 0 and B = Bc0, the Grüneisen ratio as a function of temperature T diverges. We demonstrate that both the divergence and the jump are determined by the specific low temperature behavior of the entropy S(T ) ∝ S0 + a √ T + bT with S0, a and b are temperature independent constants.PACS numbers: 71.10. Hf, 71.27.+a, 71.10.Hf, The most outstanding puzzle of heavy fermion (HF) metals is what determines their universal behavior which drastically differs from the behavior of ordinary metals. It is wide accepted that the fundamental physics observed in the HF metals is controlled by quantum phase transitions. A quantum phase transition is driven by control parameters such as composition, pressure, number density x of electrons (holes), magnetic field B, etc, and takes place at a quantum critical point (QCP) when the temperature T = 0. In the case of conventional quantum phase transitions (CQPT) the physics is dominated by thermal and quantum fluctuations near CQP. This critical state is characterized by the absence of quasiparticles. It is believed that the absence of quasiparticle-like excitations is the main cause of the non-Fermi liquid (NFL) behavior, see e.g. [1]. However, theories based on CQPT fail to explain the experimental observations of the universal behavior related to the divergence of the effective mass M * at the magnetic field tuned QCP, the specific behavior of the spin susceptibility, its scaling properties, etc.It is possible to explain the observed universal behavior of the HF metals on the basis of the fermion condensation quantum phase transition (FCQPT) which takes place at x = x F C and allows the existence of the Landau quasiparticles down to the lowest temperatures [2]. It is the quasiparticles which define the universal behavior of the HF metals at low temperatures [2,3]. In contrast to the conventional Landau quasiparticles, these are characterized by the effective mass which strongly depends on temperature T , applied magnetic field B and the number density x of the heavy electron liquid of HF metal. Thus, we come back again to the key role of the of the effective * E-mail: vrshag@thd.pnpi.spb.ru mass.On the other hand, it is plausible to probe the other properties of the heavy electron liquid w...