Phase diagram of quantum critical system via local convertibility of ground state

The study of low-dimensional quantum systems has proven to be a particularly fertile field for discovering novel types of quantum matter. When studied numerically, low-energy states of low-dimensional quantum systems are often approximated via a tensor-network description. The tensor network's utility in studying short range correlated states in 1D have been thoroughly investigated, with numerous examples where the treatment is essentially exact. Yet, despite the large number of works investigating these networks and their relations to physical models, examples of exact correspondence between the ground state of a quantum critical system and an appropriate scale-invariant tensor network have eluded us so far. Here we show that the features of the quantum-critical Motzkin model can be faithfully captured by an analytic tensor network that exactly represents the ground state of the physical Hamiltonian. In particular, our network offers a two-dimensional representation of this state by a correspondence between walks and a type of tiling of a square lattice. We discuss connections to renormalization and holography.

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Interplay between superconductivity and non-Fermi liquid behavior at a quantum-critical point in a metal. V. The γ model and its phase diagram: The case γ=2

Physical Review B ◽

10.1103/physrevb.103.184508 ◽

2021 ◽

Vol 103 (18) ◽

Author(s):

Yi-Ming Wu ◽

Shang-Shun Zhang ◽

Artem Abanov ◽

Andrey V. Chubukov

Keyword(s):

Phase Diagram ◽

Critical Point ◽

Fermi Liquid ◽

Quantum Critical Point ◽

Liquid Behavior ◽

Quantum Critical ◽

Fermi Liquid Behavior

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Ground state and stability of the fractional plateau phase in metallic Shastry–Sutherland system TmB4

Scientific Reports ◽

10.1038/s41598-021-86353-5 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Matúš Orendáč ◽

Slavomír Gabáni ◽

Pavol Farkašovský ◽

Emil Gažo ◽

Jozef Kačmarčík ◽

...

Keyword(s):

Magnetic Field ◽

Phase Diagram ◽

Ground State ◽

Constant Magnetic Field ◽

Paramagnetic Phase ◽

The Other ◽

Zero Field ◽

Plateau Phase ◽

Low Field ◽

Zero Field Cooling

AbstractWe present a study of the ground state and stability of the fractional plateau phase (FPP) with M/Msat = 1/8 in the metallic Shastry–Sutherland system TmB4. Magnetization (M) measurements show that the FPP states are thermodynamically stable when the sample is cooled in constant magnetic field from the paramagnetic phase to the ordered one at 2 K. On the other hand, after zero-field cooling and subsequent magnetization these states appear to be of dynamic origin. In this case the FPP states are closely associated with the half plateau phase (HPP, M/Msat = ½), mediate the HPP to the low-field antiferromagnetic (AF) phase and depend on the thermodynamic history. Thus, in the same place of the phase diagram both, the stable and the metastable (dynamic) fractional plateau (FP) states, can be observed, depending on the way they are reached. In case of metastable FP states thermodynamic paths are identified that lead to very flat fractional plateaus in the FPP. Moreover, with a further decrease of magnetic field also the low-field AF phase becomes influenced and exhibits a plateau of the order of 1/1000 Msat.

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