The electron quantum radar : interferometric detection of time-dependent electromagnetic fields at the sub-nanosecond time scale and using single electron excitations
Recent advances in quantum nano-electronics have lead to the manufacturing of electrical circuits in which quantum electrical currents involving one to a few electrons can be generated controlled and characterized. This breakthrough has spurred the development of sophisticated quantum sensing technologies, such as the electron quantum radar (EQR) introduced in this work. The EQR is an interferometric sensor leveraging both the sensitivity to electromagnetic fields and the long coherence time of single electrons to probe the quantum state of microwave radiations with subnanosecond time resolution. It is designed as a Mach-Zehnder interferometer (MZI) with one branch coupled to the radiation to be probed. As a single-electron propagates along both branches of the MZI, its wave function is altered by the radiation. This shift is imprinted in the interferences contribution to the average electrical current exiting the interferometer which then provides information about the radiation. Part of this work focuses on the shaping of single electron wave-packets and on the design of the radiation coupler which coupled the incoming single electron to the electromagnetic radiation to be probed. These two elements determine the EQR's resolving power for each probed radiation. Finally, the EQR's sensing capabilities are evaluated through specific examples, such as probing squeezed states or single photon detection, demonstrating its potential to measure properties of quantum radiation in both time and frequency domains in realistic forth coming experiments.
Recent advances in quantum nano-electronics have lead to the manufacturing of electrical circuits in which quantum electrical currents involving one to a few electrons can be generated controlled and characterized. This breakthrough has spurred the development of sophisticated quantum sensing technologies, such as the electron quantum radar (EQR) introduced in this work. The EQR is an interferometric sensor leveraging both the sensitivity to electromagnetic fields and the long coherence time of single electrons to probe the quantum state of microwave radiations with subnanosecond time resolution. It is designed as a Mach-Zehnder interferometer (MZI) with one branch coupled to the radiation to be probed. As a single-electron propagates along both branches of the MZI, its wave function is altered by the radiation. This shift is imprinted in the interferences contribution to the average electrical current exiting the interferometer which then provides information about the radiation. Part of this work focuses on the shaping of single electron wave-packets and on the design of the radiation coupler which coupled the incoming single electron to the electromagnetic radiation to be probed. These two elements determine the EQR's resolving power for each probed radiation. Finally, the EQR's sensing capabilities are evaluated through specific examples, such as probing squeezed states or single photon detection, demonstrating its potential to measure properties of quantum radiation in both time and frequency domains in realistic forth coming experiments.
In this study, we investigate the potential of electronic interferometers for probing the quantum state of electromagnetic radiation on a chip at subnanosecond timescales. We propose to use single-electron excitations propagating within an electronic Mach-Zehnder interferometer in the Aharonov-Bohm-dominated regime. We discuss how information about the quantum state of the electromagnetic radiation is encoded into the interference contribution to the average outgoing electrical current. By investigating squeezed radiation and single-edge magnetoplasmons probed by leviton pulses in a realistic setup, we show that single-electron interferometers have the potential to probe quantum radiation in the time domain with subnanosecond to picosecond time resolution. Our research could have significant implications for probing the fundamental properties of light in the microwave to terahertz domains at extremely short timescales.
Characterizing quantum states of the electromagnetic field at microwave frequencies requires fast and sensitive detectors that can simultaneously probe the field's time-dependent amplitude and its quantum fluctuations. So far, this has been achieved by using either homodyne detection or fast digitizers. Both methods rely on the extraction of microwave radiation through an amplification chain towards the detector placed at room temperature, thereby limiting the time resolution to the ~10-GHz bandwidth of the measurement chain. Additionally, the coupling of high-impedance samples to the 50-Ω measurement chain is very weak, setting strong limitations on the detection sensitivity. In this work, we demonstrate an on-chip quantum sensor that exploits the phase of a single-electron wavefunction, measured in an electronic Fabry-Pérot interferometer, to detect the amplitude of a classical time-dependent electric field. The interferometer is implemented in a GaAs/AlGaAs quantum Hall conductor. The time resolution, limited by the temporal width of the electronic wavepacket, is ~35 ps. The interferometry technique provides a voltage resolution of ~50 μV, corresponding to a few microwave photons. Importantly, our detector measures both phase and contrast of the interference pattern. The latter opens the way to the detection of non-classical electromagnetic fields, such as squeezed or Fock states.
This paper provides a brief introduction of the current state of quantum radar (QR) technology development, focusing on the experimental methods used for modifying QR in a laboratory setting. We delve into the foundational principles of quantum electrodynamics and consider interferometric aspects. Quantum radar systems, empowered by quantum measurements, extend their capabilities beyond conventional target detection and recognition, encompassing the detection and identification of RF stealth platforms and advanced weapons systems. Quantum technology is gaining paramount significance in various research domains, with the emergence of the concept of quantum radar, which leverages the quantum states of photons to extract information from distant targets. The mechanism involves dispatching photons, or photon clusters, toward the target, whereupon they are absorbed and subsequently re-emitted. The crucial measurement process can be executed in two distinct manners. One approach entails an interferometric measurement, often referred to as phase measurement, conducted on the photons, while the alternative method involves the straightforward quantification of returning photons. These methods are respectively known as Interferometric QR and Quantum Illumination (QI). In both approaches, one can opt to employ stationary quantum states of photons or harness entangled states. Extensive research has demonstrated that the use of entangled states yields the most significant resolution enhancement, achieving optimal results under ideal conditions. Quantum states offer a substantial advantage by virtue of their inherent correlations, referred to as quantum correlations, which augment both resolution and signal-to-noise ratio (SNR) in the radar system. This paper explores the intricacies of these advancements in quantum radar technology, shedding light on the underlying principles and experimental methodologies.
This Paper examines novel approach the advancements in Q-dots based quantum radar technology, design considerations for its integration, and quantum radar cross section (QRCS) based on interferometric and quantum electrodynamics. In addition to performing standard target detection and recognition duties, quantum radar systems with quantum measurement assistance may also detect and identify RF stealth platforms and missile systems. In numerous fields of study, the advancement of radar technology is crucial. A quantum radar is a notion that has been developed that uses photon quantum states to gather information about a distant target. A single photon or a small group of photons is directed in the direction of the target. The target absorbs the photons, which are then re-emitted into the receiver. There are two possible approaches to carrying out the measurement procedure. An interferometric analysis can be performed.one can either count the number of photons that return or perform a measurement (or phase measurement) on the photon. Since the latter technique is called Quantum Illumination, the former is called Interferometric Quantum Radar. Entangled states or stationary quantum states of photons can be used for either of those techniques. Entangled states have been demonstrated to offer the best resolution enhancement, reaching the optimum situation. Compared to classical approaches, the advantage of adopting quantum states is that they show more degrees of correlation via which information can be obtained. These additional correlations, sometimes referred to as quantum correlations, increase the radar system's potential resolution and signal/noise ratio (SNR). Relationship research between the two photons is conducted in order to gather data. Coherent state quantum radar relies on coherent state photons and a quantum detection technique to overcome the diffraction limit. The design and operating concepts of quantum applied trends are also reviewed in this work.
Quantum radar represents a promising advancement over classical radar systems by exploiting quantum mechanical phenomena such as entanglement and quantum measurement to overcome fundamental detection limitations. This paper reviews the evolution of radar technology from conventional radar frequency systems to quantum radar architectures, with emphasis on sensitivity enhancement and detection of RF-stealth targets for military defense applications. Classical radar parameters such as radar range, transmitted power and cross section are revisited and extended to their quantum analogues. The role of entangled single photon sources in improving detection performance under high noise and jamming environments is discussed. Context of microwave quantum radar is reviewed along with photonic implementations. This paper further highlights the importance of quantum measurement theory, including system-apparatus entanglement, density matrix formalism and wave function collapse in extracting information from quantum radar systems. Although significant experimental challenges remain, recent advances indicate strong potential for future development of quantum radar in next generation defense and surveillance systems.
In this dissertation we begin with a brief introduction to quantum optics concentrating on the topics of the noise of quantum optical states, quantum estimation theory, quantum interferometry and the atom-field interaction. This background is necessary for understanding the discussions in later chapters. In particular, quantum interferometry, which is optical interferometry when the light source is a quantum mechanical state, plays a central role in this dissertation. In Chapter 2 we discuss the phase estimation sensitivity of quantum metrology when photon loss is present. In Chapter 3 we extend the discussion to include the phase fluctuation of the system caused by the environment. We model our metrological system with the Mach-Zehnder interferometer (MZI) and use a light field in the symmetric number-path entangled state as the source. In both chapters we use the parity operator as the detection scheme and show that it is optimal under pure dephasing. In Chapter 4 we discuss the application of quantum optical states in remote sensing and propose a new scheme for a quantum radar. Again, our scheme consists of a MZI and a coherent light source. It is shown that using only coherent states of light and quantum homodyne detection, super-resolving ranging and angle determination are achievable. Chapter 5 is devoted to the generation of a super-resolving single-photon number-path entangled state which may serve as a proof-of-principle prototype for quantum lithography. The repeated implementation of MZIs is shown to be able to remove photons coherently from both modes of a symmetric number-path entangled state with arbitrarily high photon number. Lastly, in Chapter 6 we introduce the phenomenon known as polarization self-rotation and discuss its potential in generating a squeezed vacuum state, which has a huge impact in quantum interferometry.