Strongly Correlated Electron Systems: An Operatorial Perspective

Sergey Yu. Savrasov

Amir Eskandari-asl, Adolfo Avella

We have studied the Hubbard model on a dimer under the effect of an intense ultra-short laser pulse using the Dynamical Projective Operatorial Approach (DPOA). This shows how DPOA, stemming from the Composite Operator Method, can effectively tackle strongly correlated systems and real materials. To study the effect of the pump pulse on the anti-ferromagnetic-like order, we have analyzed the behavior of the double occupancy. It turns out that the pulse, in a specific range of its parameters, can drive the system in and out of the otherwise very robust anti-ferromagnetic-like phase that naturally emerges at half-filling and low temperatures. In such a situation, the system undergoes Rabi-like oscillations.

Masatoshi Imada, Norio Kawakami, Hiroyuki Shiba +1 more

Zhi‐Ming Yu, Yu-Liang Liu

The phase field, which originates from the electronic interaction, plays an important role in describing a strongly correlated system in one dimension. However, in higher dimensions the effect of phase field cannot be obviously understood. With the eigenfunctional theory, we calculate the pair distribution function of the three-dimensional electron gas to study the relationship between the phase field and the electronic correlation effect and show that at zero temperature the correlation effect of the electrons is mainly dominated by the phase fluctuation, which is produced by the electronic interaction. We also discuss the failure of random phase approximation in studying the correlation function when the correlation effect is strong in the view of the phase field.

Karan Aryanpour

Yuehua Su, Guoya Zhang, Chao Zhang +1 more

Research on strongly correlated electron systems faces a fundamental challenge due to the complex nature of intrinsic many-body correlations. A key strategy to address this challenge lies in advancing experimental methods that can directly probe and elucidate the underlying many-body correlations. In this perspective article, we discuss the theoretically proposed coincidence detection techniques, which are designed to directly measure two-body correlations in various particle-particle and particle-hole channels, with momentum, energy, and/or spatial resolution. We also explore the prospects of these coincidence detection techniques for future theoretical and experimental developments. The successful implementation and refinement of these coincidence detection techniques promise to deliver powerful new approaches for unraveling long-standing puzzles in strongly correlated electron systems, such as the enigmatic mechanism of unconventional superconductivity and the long-sought quantum spin liquids. Furthermore, these coincidence detection techniques will offer powerful new methods to investigate novel phenomena like itinerant magnetism and electronic nematicity in quantum materials.