Three scenarios fro valuable planetary science missions on Mars: next generation of CubeSats to support space exploration

Planetary science originally tended to make use of “flagship” missions characterized by big satellites and expensive resources. In the near future this traditional satellite paradigm could dramatically change with the introduction of very small satellites. This shift towards smaller, less expensive devices mirrors the paradigm shift that happened in the computer industry with the miniaturization of electronics, as focus has moved from massive machines to personal computer up to smart phones. The ultimate expression of spacecraft miniaturization is today represented by CubeSats, but while over a hundred CubeSats have been launched into Earth orbit, space-based research beyond LEO struggles to find practical application. CubeSat small size poses hard challenges for independent planetary exploration, nevertheless they remain highly attractive due to the reduced development time and cost coming from platform modularity and standardization, availability of COTS parts, reduced launch cost. Constellations of CubeSats, collaborative networks, fractionated or federated systems are becoming popular concepts as they can offer spatially distributed measurements and the opportunity to be used as disposable sensors with a flexibility not achievable by single-satellite platforms. We have worked towards advancing the state of the art in CubeSat missions design and implementation by defining the range of science capabilities for CubeSats beyond LEO, and by enhancing the top technological challenges to support science objectives (e.g. propulsion, communications, radiation environment protection). Planet Mars was chosen as target destination to the purpose of this work, by selecting a set of scientific objectives for CubeSats to serve astrobiology goals and future human exploration. Missions to accomplish orbital and atmospheric measurement, in situ analyses related to biosignatures detection and environmental characterization have been explored. The opportunity to rely on already existing space assets in the proximity of Mars, or on a “mothership” for data relay or orbit insertion, has been considered in this context. A tradespace exploration led to the definition of three classes of mission architectures, respectively based on surface penetrators, atmosphere scouts and orbiting fleet. Each architecture has been assessed in the perspective of science return against a set of leading indicators that draw out cost, utility, complexity, technology readiness among others. For each class a mission concept has been created, providing a basis to elicit the definition of top-level requirements and to assess the value of science return in the context of complex mission scenarios

Two-dimensional epitaxial superconductor-semiconductor heterostructures: A platform for topological superconducting networks

Progress in the emergent field of topological superconductivity relies on synthesis of new material combinations, combining superconductivity, low density, and spin-orbit coupling (SOC). For example, theory [1-4] indicates that the interface between a one-dimensional (1D) semiconductor (Sm) with strong SOC and a superconductor (S) hosts Majorana modes with nontrivial topological properties [5-8]. Recently, epitaxial growth of Al on InAs nanowires was shown to yield a high quality S-Sm system with uniformly transparent interfaces [9] and a hard induced gap, indicted by strongly suppressed sub gap tunneling conductance [10]. Here we report the realization of a two-dimensional (2D) InAs/InGaAs heterostructure with epitaxial Al, yielding a planar S-Sm system with structural and transport characteristics as good as the epitaxial wires. The realization of 2D epitaxial S-Sm systems represent a significant advance over wires, allowing extended networks via top-down processing. Among numerous potential applications, this new material system can serve as a platform for complex networks of topological superconductors with gate-controlled Majorana zero modes [1-4]. We demonstrate gateable Josephson junctions and a highly transparent 2D S-Sm interface based on the product of excess current and normal state resistance

Hybridization of sub-gap states in one-dimensional superconductor/semiconductor Coulomb islands

We present measurements of one-dimensional superconductor-semiconductor Coulomb islands, fabricated by gate confinement of a two-dimensional InAs heterostructure with an epitaxial Al layer. When tuned via electrostatic side gates to regimes without sub-gap states, Coulomb blockade reveals Cooper-pair mediated transport. When sub-gap states are present, Coulomb peak positions and heights oscillate in a correlated way with magnetic field and gate voltage, as predicted theoretically, with (anti) crossings in (parallel) transverse magnetic field indicating Rashba-type spin-orbit coupling. Overall results are consistent with a picture of overlapping Majorana zero modes in finite wires

Modelo de automação do processo de compra para laboratórios.

Os laboratórios desempenham um papel de extrema relevância nos centros de pesquisa, com toda a gama de serviços que prestam ao processo de PD&I. Entretanto, a qualidade desses serviços depende, em grande parte, da aquisição de reagentes e materiais utilizados nos experimentos e nas análises laboratoriais. Especificações incompletas e consolidação manual de informações contribuem para a morosidade do processo de compra. Para minimizar esse problema, construiu-se um modelo experimental embasado no aplicativo Excel, que padroniza e automatiza as etapas desse processo. A estruturação do modelo foi feita da seguinte forma: i) planilha, por solicitante, com especificação completa de reagentes e materiais para laboratórios (baseada em histórico de compras), com campos para seleção dos itens desejados e inserção de quantitativos por projeto; ii) planilha de controle orçamentário com indicação de valores financeiros solicitados por projeto, campos para inserção de valores disponíveis no Sistema de Acompanhamento Orçamentário (SAO) e saldo por projeto; iii) planilha de consolidação automática das demandas, com identificação dos demandantes e projetos correlacionados; iv) planilha para coleta de preço, separada por lote; v) planilha de acompanhamento do pedido, com indicação do número de propostas recebidas dos fornecedores; vi) planilha com as especificações que serão usadas no Edital de compra. A simulação do modelo com um número pequeno de variáveis de entrada (materiais, solicitantes, etc.) mostrou que ele automatiza uma série de cálculos, classifica e disponibiliza as informações do pedido de compra numa formatação que facilita a coleta de preço e as especificações dos itens no Edital de licitação, acelerando a realização de compras destinadas aos laboratórios. A próxima etapa compreenderá os testes de validação desse modelo numa situação real de compra para laboratórios.bitstream/item/50895/1/201-Modelo-de-automacao-Jairo.pdfResumo

Flip-chip-based fast inductive parity readout of a planar superconducting island

Properties of superconducting devices depend sensitively on the parity (even or odd) of the quasiparticles they contain. Encoding quantum information in the parity degree of freedom is central in several emerging solid-state qubit architectures. Yet, accurate, non-destructive, and time-resolved parity measurement is a challenging and long-standing issue. Here we report on control and real-time parity measurement in a superconducting island embedded in a superconducting loop and realized in a hybrid two-dimensional heterostructure using a microwave resonator. Device and readout resonator are located on separate chips, connected via flip-chip bonding, and couple inductively through vacuum. The superconducting resonator detects the parity-dependent circuit inductance, allowing for fast and non-destructive parity readout. We resolved even and odd parity states with signal-to-noise ratio SNR $\approx3$ with an integration time of $20~\mu$s and detection fidelity exceeding 98%. Real-time parity measurement showed state lifetime extending into millisecond range. Our approach will lead to better understanding of coherence-limiting mechanisms in superconducting quantum hardware and provide novel readout schemes for hybrid qubits

Spin-degeneracy breaking and parity transitions in three-terminal Josephson junctions

Harnessing spin and parity degrees of freedom is of fundamental importance for the realization of emergent quantum devices. Nanostructures embedded in superconductor--semiconductor hybrid materials offer novel and yet unexplored routes for addressing and manipulating fermionic modes. Here we spectroscopically probe the two-dimensional band structure of Andreev bound states in a phase-controlled hybrid three-terminal Josephson junction. Andreev bands reveal spin-degeneracy breaking, with level splitting in excess of 9 GHz, and zero-energy crossings associated to ground state fermion parity transitions, in agreement with theoretical predictions. Both effects occur without the need of external magnetic fields or sizable charging energies and are tuned locally by controlling superconducting phase differences. Our results highlight the potential of multiterminal hybrid devices for engineering quantum states

Zeeman and Orbital Driven Phase Transitions in Planar Josephson Junctions

We perform supercurrent and tunneling spectroscopy measurements on gate-tunable InAs/Al Josephson junctions (JJs) in an in-plane magnetic field, and report on phase shifts in the current-phase relation measured with respect to an absolute phase reference. The impact of orbital effects is investigated by studying multiple devices with different superconducting lead sizes. At low fields, we observe gate-dependent phase shifts of up to ${\varphi_{0}=0.5\pi}$ which are consistent with a Zeeman field coupling to highly-transmissive Andreev bound states via Rashba spin-orbit interaction. A distinct phase shift emerges at larger fields, concomitant with a switching current minimum and the closing and reopening of the superconducting gap. These signatures of an induced phase transition, which might resemble a topological transition, scale with the superconducting lead size, demonstrating the crucial role of orbital effects. Our results elucidate the interplay of Zeeman, spin-orbit and orbital effects in InAs/Al JJs, giving new understanding to phase transitions in hybrid JJs and their applications in quantum computing and superconducting electronics

Microwave-induced conductance replicas in hybrid Josephson junctions without Floquet-Andreev states

Light-matter interaction enables engineering of non-equilibrium quantum systems. In condensed matter, spatially and temporally cyclic Hamiltonians are expected to generate energy-periodic Floquet states, with properties inaccessible at thermal equilibrium. A recent work explored the tunnelling conductance of a planar Josephson junction under microwave irradiation, and interpreted replicas of conductance features as evidence of steady Floquet-Andreev states. Here we realise a similar device in a hybrid superconducting-semiconducting heterostructure, which utilises a tunnelling probe with gate-tunable transparency and allows simultaneous measurements of Andreev spectrum and current-phase relation of the planar Josephson junction. We show that, in our devices, spectral replicas in sub-gap conductance emerging under microwave irradiation are caused by photon assisted tunnelling of electrons into Andreev states. The current-phase relation under microwave irradiation is also explained by the interaction of Andreev states with microwave photons, without the need to invoke Floquet states. The techniques outlined in this study establish a baseline to distinguish photon assisted tunnelling from Floquet-Andreev states in mesoscopic devices, a crucial development towards understanding light-matter coupling in hybrid nanostructures

Relating Andreev Bound States and Supercurrents in Hybrid Josephson Junctions

We investigate superconducting quantum interference devices consisting of two highly transmissive Josephson junctions coupled by a superconducting loop, all defined in an epitaxial InAs/Al heterostructure. A novel device design allows for independent measurements of the Andreev bound state spectrum within the normal region of a junction and the resulting current-phase relation. We show that knowledge of the Andreev bound state spectrum alone is enough to derive the independently measured phase dependent supercurrent. On the other hand, the opposite relation does not generally hold true as details of the energy spectrum are averaged out in a critical current measurement. Finally, quantitative understanding of field dependent spectrum and supercurrent require taking into account the second junction in the loop and the kinetic inductance of the epitaxial Al film