Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Evidence for gradual evolution of low-energy fluctuations underlying the
  first-order structural and valence order in YbPd   The valence orders at $T_a=125$ K and $T_b=105$ K in the cubic compound YbPd
have been investigated by $^{105}$Pd-nuclear magnetic resonance (NMR)
measurements. Significant decrease in the density of states at the Fermi energy
below $T_a$ is evident from the measurement of nuclear spin lattice relaxation
rate $1/T_1$, suggesting that the instabilities of Fermi surface are associated
with the transitions. Moreover we observed the unusual evolution of low-energy
fluctuations toward the valence transition at $T_a$ behind its drastic
first-order nature. The structural transition accompanying the valence order
may occur as a result of cooperative effect of Fermi surface and valence
instabilities.

33
The categories of this paper are: plasm-ph
19
The categories of this paper are: eess
17
The categories of this paper are: q-fin
25
The categories of this paper are: patt-sol
30
The categories of this paper are: q-alg
16
The categories of this paper are: stat
13
The categories of this paper are: quant-ph
24
The categories of this paper are: dg-ga
11
The categories of this paper are: hep-lat
21
The categories of this paper are: adap-org
8
The categories of this paper are: hep-ex
22
The categories of this paper are: chao-dyn
5
The categories of this paper are: gr-qc
35
The categories of this paper are: mtrl-th
31
The categories of this paper are: ao-sci
27
The categories of this paper are: comp-gas