SciPost Submission Page
Insulator phases of Bose-Fermi mixtures induced by intraspecies next-neighbor interactions
by Felipe Gómez-Lozada, Roberto Franco, Jereson Silva-Valencia
Submission summary
| Authors (as registered SciPost users): | Jereson Silva |
| Submission information | |
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| Preprint Link: | https://arxiv.org/abs/2309.05594v2 (pdf) |
| Date submitted: | 2024-07-26 16:48 |
| Submitted by: | Silva, Jereson |
| Submitted to: | SciPost Physics |
| Ontological classification | |
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| Academic field: | Physics |
| Specialties: |
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| Approach: | Computational |
Abstract
We study a one-dimensional mixture of two-color fermions and scalar bosons at the hardcore limit, focusing on the effect that the intraspecies next-neighbor interactions have on the zero-temperature ground state of the system for different fillings of each carrier. Exploring the problem's parameters, we observed that the non-local interaction could favor or harm the well-known mixed Mott and spin-selective Mott insulators. We also found the emergence of three unusual insulating states with charge density wave (CDW) structures in which the orders of the carriers are out of phase with each other. For instance, the immiscible CDW appears only at half-filling bosonic density, whereas the mixed CDW state is characterized by equal densities of bosons and fermions. Finally, the spin-selective CDW couples the bosons and only one kind of fermions. Appropriate order parameters were proposed for each phase to obtain the critical parameters for the corresponding superfluid-insulator transition. Our results can inspire or contribute to understanding experiments in cold-atom setups with long-range interactions or recent reports involving quasiparticles in semiconductor heterostructures.
Author indications on fulfilling journal expectations
- Provide a novel and synergetic link between different research areas.
- Open a new pathway in an existing or a new research direction, with clear potential for multi-pronged follow-up work
- Detail a groundbreaking theoretical/experimental/computational discovery
- Present a breakthrough on a previously-identified and long-standing research stumbling block
Current status:
Reports on this Submission
Strengths
1- identifying phases with insulating and density wave character in Bose-Fermi mixtures in one dimension
2- a rather large scan over parameter space in a model that has plenty of tuning knobs
Weaknesses
- given the large local Hilbert space, the DMRG convergence is difficult
- no discussion of phase transitions
- no discussion of gapless phases; ie, a lot of physics is missing
- as all parameters are in a regime of very large potential energy compared to kinetic energy, how much of the phase diagrams can be understood from mean-field or Gutzwiller types of approaches?
- I find it hard to believe that no supersolids nor phases like CDW+superfluid are found.
Report
In "Insulator phases of Bose–Fermi mixtures induced by intraspecies next-neighbor interactions" the authors look at density wave structures in 1D Bose-Fermi hubbard models. They employ DMRG and provide several scans over bosonic chemical potentials at fixed fermionic densities. Most of the found density wave structures can be thought of small unit cells in which the bosonic and fermionic densities form commensurate combinations. The results are therefore not very surprising; in fact, the interesting physics in these models is usually found when tuning away from these near-classical configurations. In this sense I do not think that the paper meets the standards of a Scipost Physics paper. Either the authors can add something truly novel and unexpected, or they should consider a journal of substantially lower rank.
additional minor remarks:
- given the hard-core nature of the bosons, what is their difference from the fermions up to a trivial Jordan-Wigner factor? I have not understood the differences between the presented results and the putative ones of the same system consisting of a 3-component hard-core bosonic system
- on p4, when referring to cold atoms (refs 84-85), one should also include the scattering lengths as those cannot be chosen at will
- in Fig 1, I am confused about the "white areas" mentioned in the caption. What is meant with that? I only see white areas and lines.
- Fig 2b: is there a fermionic charge gap?
- Fig 2b: why is this referred to as incommensurate? If we take 6 lattice sites, we will definitely find an integer number of particles.
- Fig 6a, what is the small feature at rho_B = 0.2?
- Fig 11b,c: what is the meaning of the tiny plateau at rho_b = 0.4?
Requested changes
On top of the comments made above I think the paper would benefit from a table summarizing the phases found and their respective order parameters
Recommendation
Accept in alternative Journal (see Report)