The general objectives of the TopoCold project can be listed as follows:
(A) Realization of topological properties in quantum-engineered systems (cold-atoms and photonics);
(B) Identification of novel topological phenomena and probes in ultracold atoms;
(C) Study the possibility of manipulating topological excitations in ultracold topological matter;
(D) Exploration of the classification of topological matter and higher-dimensional states;
(E) Stabilization and characterization of topological systems in the presence of interactions.
The main contributions of TopoCold are indicated below:
(1) Analysis of instabilities in ultracold periodically-driven (Floquet-engineered) bosonic matter [Objectives A and E]:
- Parametric Instability Rates in Periodically-Driven Band Systems,
Phys. Rev. X 7, 021015 (2017)
- Parametric instabilities of interacting bosons in periodically-driven 1D optical lattices,
Physical Review X 10, 011030 (2020)
- Parametric instabilities in a 2D periodically-driven bosonic system: Beyond the weakly-interacting regime,
Phys. Rev. X 9, 011047 (2019)
(2) Realizing artificial gauge fields and topological modes in periodically-driven photonic lattices [Objective A]:
- Experimental observation of anomalous topological edge modes in a slowly-driven photonic lattice,
Nature Communications 8,13918 (2017)
- Experimental observation of Aharonov-Bohm cages in photonic lattices,
Phys. Rev. Lett. 121, 075502 (2018)
- State-recycling and time-resolved imaging in topological photonic lattices,
Nature Communications, 9, 4209 (2018)
(3) Novel methods for probing the geometry and topology of many-body quantum systems based on excitation-rate measurements (including experimental validation) [Objective B]:
- Probing topology by “heating”: Quantized circular dichroism in ultracold atoms,
Science Advances 3, e1701207 (2017)
- Extracting the quantum metric tensor through periodic driving,
Phys. Rev. B 97, 201117(R) (2018)
- Measuring quantized circular dichroism in ultracold topological matter,
Nature Physics 15, 449 (2019)
- Experimental measurement of the quantum geometric tensor using coupled qubits in diamond,
National Science Review 7, 254 (2020)
(4) Exploration of higher-form (tensor) gauge fields in condensed-matter physics and their topological defects (tensor monopoles) [Objective D]:
- Revealing tensor monopoles through quantum-metric measurements,
Phys. Rev. Lett. 121, 170401 (2018)
- A synthetic monopole source of Kalb-Ramond field in diamond,
Science 375, 1017 (2022)
(5) Cold-atom implementations of lattice gauge theories [Objective A and E]:
- Coupling ultracold matter to dynamical gauge fields in optical lattices: From flux-attachment to Z2 lattice gauge theories,
Science Advances 5, eaav7444 (2019)
- Floquet approach to ℤ2 lattice gauge theories with ultracold atoms in optical lattices,
Nature Physics 15, 1168 (2019)
(6) Anomalous Floquet systems in quantum gases [Objectives A and B]:
- Realization of an anomalous Floquet topological system with ultracold atoms,
Nature Physics (2020);
(7) Non-Abelian Bloch oscillations as novel probes for higher-order topological systems [Objective B and D]:
- Non-Abelian Bloch oscillations in higher-order topological insulators,
Nature Communications 11, 5942 (2020) + Editors’ Highlights
(8) Realization and probing of fractional Chern insulators in cold atoms [Objective E]:
- Detecting fractional Chern insulators through circular dichroism,
Phys. Rev. Lett. 122, 166801 (2019); PRL Editors’ Suggestion
- Fractional Chern insulators of few bosons in a box:
Hall plateaus from center-of-mass drifts and density profiles,
Phys. Rev. A 102, 063316 (2020)
(9) Quantum Fisher information measurements in NV centers [Objective B]:
- Experimental estimation of the quantum Fisher information from randomized measurements,
M. Yu, D. Li, J. Wang, Y.Chu P. Yang, M. Gong, N. Goldman and J. Cai,
Phys. Rev. Research 3, 043122 (2021)
- Quantum Fisher information measurement and verification of the quantum Cramér-Rao bound in a solid-state qubit,
M. Yu, Y. Liu, P. Yang, M. Gong, Q. Cao, S. Zhang, H. Liu, M. Heyl, T. Ozawa, N. Goldman, and J. Cai,
npj Quantum Information 8, 56 (2022)
(10) Non-linear topological excitations [Objective C]
- Quantized transport of solitons in nonlinear Thouless pumps:
From Wannier drags to ultracold topological mixtures,
Nature Communications 13, 5997 (2022)
