Abstract This study presents the design and analysis of a specialized RF/MW circuit named the Quantum Non-classicality Enhancing Circuit, specifically developed for quantum applications. The primary objective is to reduce the noise figure within the operational frequency range of 4–8 GHz to enhance non-classical properties in quantum signals. To achieve this, a HEMT was chosen due to its exceptional noise reduction capabilities, which are critical for quantum engineering. While targeting a noise figure of less than 0.065 dB within the specified frequency band, a trade-off with gain was identified. This issue was addressed by introducing additional amplification stages to stabilize the noise figure without compromising overall performance. Quantum analysis of the circuit, based on a simplified HEMT model, provided valuable insights into its nonlinear behavior and the interaction between circuit components and environmental factors. Using the QuTiP toolbox in Python, a time-evolution analysis of the system was conducted, revealing the circuit’s response as an open quantum system under cryogenic conditions. The study also explores the relationship between quantum correlation (measured by quantum discord) and the noise figure, raising significant questions about the impact of noise minimization on enhancing non-classicality at low temperatures. Alongside the quantum analysis, a detailed circuit layout was designed and optimized to minimize the noise figure. The findings from the quantum analysis demonstrated that non-classicality generation and noise minimization share a common foundation, reinforcing the design approach. This comprehensive study highlights the complex interplay between circuit design and quantum properties, offering a strategic path toward improved quantum signal processing at cryogenic temperatures.
Abstract This study presents the design and analysis of a specialized RF/MW circuit named the Quantum Non-classicality Enhancing Circuit, specifically developed for quantum applications. The primary objective is to reduce the noise figure within the operational frequency range of 4–8 GHz to enhance non-classical properties in quantum signals. To achieve this, a HEMT was chosen due to its exceptional noise reduction capabilities, which are critical for quantum engineering. While targeting a noise figure of less than 0.065 dB within the specified frequency band, a trade-off with gain was identified. This issue was addressed by introducing additional amplification stages to stabilize the noise figure without compromising overall performance. Quantum analysis of the circuit, based on a simplified HEMT model, provided valuable insights into its nonlinear behavior and the interaction between circuit components and environmental factors. Using the QuTiP toolbox in Python, a time-evolution analysis of the system was conducted, revealing the circuit’s response as an open quantum system under cryogenic conditions. The study also explores the relationship between quantum correlation (measured by quantum discord) and the noise figure, raising significant questions about the impact of noise minimization on enhancing non-classicality at low temperatures. Alongside the quantum analysis, a detailed circuit layout was designed and optimized to minimize the noise figure. The findings from the quantum analysis demonstrated that non-classicality generation and noise minimization share a common foundation, reinforcing the design approach. This comprehensive study highlights the complex interplay between circuit design and quantum properties, offering a strategic path toward improved quantum signal processing at cryogenic temperatures.
In this study, we present the design and analysis of a Low Noise Amplifier tailored specifically for quantum applications. We selected the HEMT for its unique noise reduction properties, crucial for quantum engineering. The main goal is to minimize the noise figure within the C-band frequency range (4-8 GHz) to induce nonclassicality in quantum signals. While achieving a noise figure of less than 0.065 dB within this band, we recognized the trade-off with gain, mitigated by incorporating additional stages to maintain noise figure at optimal levels. Quantum analysis of the circuit, employing a simplified model of HEMT due to its complexity, revealed insights into its nonlinear properties and interactions between circuit components and environmental factors. Leveraging Qutip toolbox in Python, we conducted time-evolution analysis of the system, revealing the circuit's behavior as an open quantum system under cryogenic conditions. Our investigation extends to quantifying quantum correlation (quantum discord) and its relationship with noise figure, posing important questions regarding the direct impact of its minimization on circuit nonclassicality at cryogenic temperatures. This comprehensive study sheds light on the intricate interplay between circuit design, and its influence on the relationship between the noise figure and quantum correlation.
This study unveils a groundbreaking exploration of using semiconductor technology in quantum circuitry. Leveraging the unique operability of 45 nm CMOS technology at deep cryogenic temperatures (~ 300 mK), a novel quantum electronic circuit is meticulously designed. Through the intricate coupling of two matching circuits via a 45 nm nMOS transistor, operating as an open quantum system, the circuit quantum Hamiltonian and the related Heisenberg-Langevin equation are derived, setting the stage for a comprehensive quantum analysis. Central to this investigation are three pivotal coefficients derived, which are the coupling between the coupled oscillator charge and flux operators through the internal circuit of the transistor. These coefficients emerge as critical determinants, shaping both the circuit potential as a parametric amplifier and its impact on quantum properties. The study unfolds a delicate interplay between these coefficients, showcasing their profound influence on quantum discord and the gain of the parametric amplifier. Consequently, the assimilation of 45 nm CMOS technology with quantum circuitry makes it possible to potentially bridge the technological gap in quantum computing applications, where the parametric amplifier is a necessary and critical device. The designed novel quantum device serves not only as a quantum parametric amplifier to amplify quantum signals but also enhances the inherent quantum properties of the signals such as non-classicality. Therefore, one can create an effective parametric amplifier that simultaneously improves the quantum characteristics of the signals. The more interesting result is that if such a theory becomes applicable, the circuit implemented in the deep-cryogenic temperature can be easily compatible with the next step of circuitry while keeping the same electronic features compatibility with the quantum processor.
Abstract The present article primarily focuses on the design of an ultra-low-noise amplifier specifically tailored for quantum applications. The circuit design places a significant emphasis on improving the noise figure, as quantum-associated applications require the circuit's noise temperature to be around 0.4 K. This requirement aims to achieve performance comparable to the Josephson Junction amplifier. Although this task presents considerable challenges, the work concentrates on engineering the circuit to minimize mismatch and reflection coefficients, while simultaneously enhancing circuit transconductance. These efforts aim to improve the noise figure as efficiently as possible. The results of this study indicate the possibility of achieving a noise figure of approximately 0.009 dB for a unique circuit design operating at 10 K. In a departure from traditional approaches, this study employs quantum mechanical theory to analyze the circuit comprehensively. By employing quantum theory, the researchers derive relationships that highlight the crucial quantities upon which the circuit design should focus to optimize the noise figure. For example, the circuit's gain power, which depends on the circuit's photonic modes, is theoretically derived and found to affect the noise figure directly. Ultimately, by merging quantum theory with engineering approaches, this study successfully designs a highly efficient circuit that significantly minimizes the noise figure in a quantum application setting.
In recent years, quantum computers have emerged as a disruptive technology capable of solving problems currently intractable for classical systems. Computation is performed using qubits, which exploit quantum properties like superposition and entanglement, and requires them to operate at cryogenic temperatures. As a result, quantum computers are built around cryostats that reach temperatures as low as \qty{10}{\milli\kelvin}. However, to deliver a significant advantage over conventional approaches, quantum computers must increase their qubit count, improve qubit quality, and adopt more sophisticated control and readout architectures. The integration of more complex or improved cryogenic electronics inside the cryostat can enhance the scalability of these systems, and is the topic of this thesis. The primary technology platform used in this work is based on cryogenic InGaAs/InP high-electron-mobility transistors (HEMTs). One objective was the development of cryogenic circuits that enhance the scalability of spin-qubit quantum computers by enabling efficient signal delivery in control and readout paths. To this end, cryogenic multiplexers were demonstrated with threshold voltages as low as \qty{90}{\milli\volt}, subthreshold swing of \qty{5}{\milli\volt\per dec}, and on-off ratio of 107 at \qty{4}{\kelvin}. In addition, a charge-storage array was developed for the local generation of qubit bias signals, using an operation scheme based on pulse trains to program voltage levels on capacitors that can be placed in proximity to qubit gates. A second objective was the fabrication of HEMTs with enhanced performance for use in cryogenic low-noise amplifiers, which are critical for qubit readout. Studies were performed to characterize self-heating, an effect that limits transistor performance at cryogenic temperatures. Moreover HEMTs with improved characteristics were fabricated, which achieved exceptional values in state-of-the-art metrics, including fT= \qty{622}{\giga\hertz}, fMAX= \qty{733}{\giga\hertz}, and a noise indication factor IDS/gm= \qty{0.17}{\sqrt{\volt \cdot \milli\meter / \siemens}} at \qty{4}{\kelvin}. These results represent a new record for the combination of high-frequency and low-noise performance in a cryogenic HEMT. These results establish the InGaAs/InP HEMT technology as a promising platform for the development of cryogenic circuits, and demonstrate its versatility in addressing multiple applications requiring both single-device performance and integration at the circuit level.
The cryogenic indium phosphide (InP) high-electron-mobility transistor (HEMT) low-noise amplifier (LNA) is used for the readout amplification of qubits at4K where cooling capabilities are limited implying that the dc power of the active circuits is an essential design constraint. In this article, the RF and noise performance of the InP HEMT under ultralow-power (ULP) operation at4K has been characterized. The small-signal and noise parameter model of the InP HEMT was extracted down to 1μW. The tradeoff between noise performance and dc power consumption was analyzed in terms of the drain current and drain voltage. A 4–6 GHz hybrid cryogenic HEMT LNA designed for qubit readout and optimized for lowest noise below1mW dc power consumption was fabricated. The measured performance of the LNA at4K attained 23.1 dB average gain and 2.0 K average noise temperature at 200μW dc power.
The integration of quantum and classical model is essential for understanding the behaviour of quantum system operating in cryogenic environments. In this work we present a comprehensive simulation framework that combines quantum dots-based Grover-like state generation, cryogenic low noise amplifier (Cryo-LNA) behaviour, and classical LC circuit dynamics. The quantum circuit is simulated using matrix-based operations to evaluate the probability amplitudes of 3 q-bits of quantum state representing Grover-like search behaviour. The performance characteristics of cryo-LNA, including S11 (reflection confection), S21 (Gain), return loss and noise figure are modelled across a wide frequency spectrum to evaluate the amplifier’s behaviour at cryogenic temperature. Additionally, we drive and visualize the classical Lagrangian and Hamiltonian for an LC oscillator, providing insight into energy exchange and time evaluation relevant to superconducting q-bits circuit. The preposed simulation highlights the interplay between quantum signal generation and classical amplifier’s performance, offering a hybrid design approach for quantum hardware system operating at cryogenic condition’s.