Transition metal dichalcogenides (TMDs) are one of the most explored classes of two-dimensional materials. The experimental routes for synthesis and device construction in these materials are well established allowing future applications. Materials with topological phases of matter present the possibility of electronic transport with long coherence length, due to the protection of their surface states by time-reversal symmetry. Such systems allow for the development of low-power electronics and new device functionalities. We show that energetically favorable defects in TMDs, Hg doping, and chalcogen vacancies, introduce topological states in their semiconductor gap. The transition from trivial to non-trivial occurs at a critical concentration of defects and is robust against disorder.

Qubits are the standard basis for quantum computation with many competing host platforms such as superconducting circuits, trapped ions, and quantum dots, to name a few. Part of the recent efforts with these platforms focused on simulations of fermionic systems. However, the mapping from qubits to local fermionic modes is inefficient because it introduces additional overhead to the calculations. To overcome this limitation, we propose a practical implementation of a universal quantum computer that uses local fermionic modes rather than qubits. Our design consists of quantum dots tunnel coupled by a hybrid superconducting island together with a tunable capacitive coupling between the dots. We show that coherent control of Cooper pair splitting, elastic cotunneling, and Coulomb interactions allows us to implement the universal set of quantum gates. Finally, we discuss possible limitations of the device and list necessary experimental efforts to overcome them. Particularly, we predict short coherence times due to charge noise and develop an alternative operational regime using neutral Andreev fermions.

We study the projective nature of quantum measurements to achieve quantum-enhanced magnetometry using a spin chain probe for remotely detecting a local magnetic field [1, 2]. Our protocol involves performing a sequence of local measurements followed by free evolution on a spin chain probe initialized in a separable state. The local magnetic field to be estimated acts on one end of the probe, inducing an evolution through the whole system. On the other hand, the readout spin, measured sequentially at regular intervals on a fixed basis, is located at the other end, enabling remote sensing of the local field. The system is not reset until the entire sequence of measurements is completed. Increasing the sequence length demonstrates that sensing precision can be enhanced beyond the standard limit. The sequential protocol has both fundamental and practical implications. From a fundamental point of view, it introduces a new methodology for achieving quantum-enhanced sensitivity by exploiting the quantum nature of measurements and their subsequent wave-function collapse. From a practical perspective, our protocol provides remote quantum sensing while avoiding the need for complex entangled states and challenging adaptive measurements.
[1] V Montenegro, GS Jones, S Bose, A Bayat - Physical Review Letters 129, 120503, 2022
[2] Y Yang, V Montenegro, A Bayat - Physical Review Research 5, 043273, 2023

Após a Revolução Industrial o mundo vivenciou mudanças profundas na sociedade. Industrialização de países, urbanização e desenvolvimento de grandes cidades e uma cultura de consumo por bens, trouxe consigo geração de poluentes, demanda por recursosnaturais e uma dependência profunda por energia para poder manter esse novo estilo devida.

É dentro desse contexto que nasce a necessidade pelo desenvolvimento de novastecnologias capazes de garantir uma geração de energia sustentável e eficiente e por soluções que possam identificar e captar poluentes no meio ambiente.

Assim, este trabalho tem por objetivo sintetizar óxidos mistos do tipo perovskitas,estudar as suas propriedades físicas e químicas obtidas a partir da sua fabricação por diferentes elementosquímicos, estequiometria e geometria visando a sua aplicação como fotossensores e células fotovoltaicas. A síntese e caracterização de monocristais serão produzidos através da técnica detransporte químico em fase vapor (CVT), nanocompostos serão obtidos pelo método sol-gel e filmes finos por meio da técnica sputtering. Mais especificamente procura-se desenvolver sensores de gases de pequeno porte que sejam mais acessíveis, apresentando alta sensibilidade e uma melhor capacidade de seleção.

Skyrmionics stands as one of physics' most promising areas, with the potential to innovate and develop future devices and technologies. Magnetic skyrmions are nanoscale magnetic whirls that are topologically protected and can be moved by currents, leading to the prediction of several applications. Its topological charge leads to high stability; however, it also leads to the skyrmion Hall effect. From memory storage devices, like the racetrack memory, to computing devices, like artificial neurons, this shortcoming is one of the primary reasons why skyrmion-based spintronic devices have yet to be achieved. Here, we study the motion of skyrmions with different topological charges and helicities. Using an effective center-of-mass description of these magnetic quasiparticles, namely, the Thiele equation, we analyze their dynamics under different gradient landscapes and interactions aiming to suppress or take advantage of the skyrmion Hall effect. Following a neuroscience approach, we also discuss possible applications in neuromorphic computing.

[1] I.R, de Assis, et al. Phys. Rev. B 108, 144438 (2023)
[2] I.R, de Assis, et al. Neuromorph. Comput. Eng. 3 014012 (2023)