Even- and odd-frequency pairing correlations in the one-dimensional t-J-h model: A comparative study

An equal-time version of odd-frequency pairing for a generalized t-J model is introduced. It is shown that the composite operators describing binding of Cooper pairs with magnetization fluctuations naturally appear in this approach. The pairing correlations in both BCS and odd-frequency channels are investigated exactly in one-dimensional systems with up to 16 sites. Our results indicate that at some range of parameters odd-frequency correlations become comparable, but smaller than BCS pairing correlations. It is speculated that the spin and density fluctuations in the frustrated model lead to the enhancement of the odd gap susceptibilities.