We propose a novel protocol for quantum illumination: quantum-enhanced noise radar. A two-mode squeezed state, which exhibits continuous-variable entanglement between so-called signal and idler beams, is used as input to the radar system. Compared existing proposals illumination, our does not require joint measurement of beams. This greatly enhances practicality system by, instance, eliminating need memory store idler. perform proof-of-principle experiment in microwave regime, directly...

Engineering light-matter interactions at the quantum level has been central to pursuit of optics for decades. Traditionally, this done by coupling emitters, typically natural atoms and ions, quantized electromagnetic fields in optical microwave cavities. In these systems, emitter is approximated as an idealized dipole, its physical size orders magnitude smaller than wavelength light. Recently, artificial made from superconducting circuits have enabled new frontiers coupling, including study...

We built and evaluated a prototype quantum radar, which we call two-mode squeezing (QTMS) in the laboratory. It operates solely at microwave frequencies; there is no downconversion from optical frequencies. Because signal generation process relies on mechanical principles, system considered to contain quantum-enhanced radar transmitter. This transmitter generates pair of entangled signals transmits one them through free space, where measured using simple rudimentary receiver. At heart device...

There has been a growing interest in realizing quantum simulators for physical systems where perturbative methods are ineffective. The scalability and flexibility of circuit electrodynamics (cQED) make it promising platform to implement various types simulators, including lattice models strongly-coupled field theories. Here, we use multimode superconducting parametric cavity as hardware-efficient analog simulator, synthetic dimensions with complex hopping interactions. coupling graph,...

Spontaneous parametric downconversion (SPDC) has been a key enabling technology in exploring quantum phenomena and their applications for decades. For instance, traditional SPDC, which splits high energy pump photon into two lower photons, is common way to produce entangled pairs. Since the early realizations of researchers have thought generalize it higher order, e.g., triplets. However, directly generating triplets through single SPDC process remained elusive. Here, using flux-pumped...

We show that the states generated by a three-mode spontaneous parametric downconversion (SPDC) interaction Hamiltonian possess tripartite entanglement of different nature to other paradigmatic entangled combination two-mode SPDCs interactions. While SPDC generates gaussian whose can be characterized standard criteria based on quantum correlations, these fail capture SPDC. use built from correlation functions class recently in superconducting-circuit implementation ideally have entanglement,...

In this work we propose two protocols to make an effective gauge potential for microwave photons in circuit QED. The schemes consist of coupled transmons whose flux are harmonically modulated time. We investigate the effect various types capacitive and inductive couplings, role fixed phase offset each site on complex coupling rate between qubits. These configurations can be directly realised a superconducting is easily extendable scalable lattice. Due intrinsic non-linearity transmon qubits...

The generation and distribution of entanglement is a central topic in quantum information science, enabling important applications communication computing. This has created great interest creating ``flying'' entangled states. authors present parametric cavity that generates multimode states microwave photons with programmable structure. advance will facilitate progress range fields, including cluster states, error-correctable logical qubits for communication, the simulation relativistic...

We demonstrate the full functionality of a circuit that generates single microwave photons on demand, with wave packet can be modulated near-arbitrary shape. achieve such high tunability by coupling superconducting qubit near end semi-infinite transmission line. A dc quantum interference device shunts line to ground and is employed modify spatial dependence electromagnetic mode structure in This control allows us couple decouple from line, shaping its emission rate fast time scales. Our...

We characterize a novel Josephson parametric amplifier based on flux-tunable quarter-wavelength resonator. The fundamental resonance frequency is ~1GHz, but we use higher modes of the resonator for our measurements. An on-chip tuning line allows magnetic flux pumping amplifier. investigate and compare degenerate amplification, involving single mode, nondegenerate using pair modes. show that reach quantum-limited noise performance in both cases, added can be less than 0.5 photons case low gain.

We describe an experiment which comes very close to implementing a quantum radar based on entangled microwaves. A pair of microwave beams are generated using Josephson parametric amplifier (JPA) and measured by digitizers after amplification. present receiver operating characteristic (ROC) curve for the case where signal power at is −83.84 dBm (corresponding JPA output, before amplification, −148.26 dBm), as well classically correlated source attempts approximate covariance structure...

We have built and evaluated a prototype quantum radar in the laboratory which operates at microwave frequencies. Because signal generation process relies on mechanical principles, system is considered to contain quantum-enhanced transmitter. This transmitter generates pair of entangled signals transmits one them through free space, where one-way measured using simple rudimentary receiver. The type entanglement used called two-mode squeezed vacuum (TMSV), so we may call our squeezing (QTMS...

In superconducting qubit measurements, stray infrared photons lead to damping processes that degrade quantum coherence. this Letter, we show a thermal blocking filter made of multiwalled carbon nanotubes diluted in stainless steel powder can significantly improve the energy relaxation time, T1, and pure dephasing Tφ, qubit. By using two independent measurement lines, with without filter, switching between them situ, observe there is an increase more than 61% T1 291% Tφ. We characterize...

Broadly speaking, in quantum illumination we can say that a proposed protocol has "quantum advantage" if it outperforms all possible classical protocols. In the optical domain of LIDAR, this is most useful metric as lasers routinely produce nearly ideal states light at room temperature (RT). This not case microwave RADAR where photon energy much less than 300K thermal energy, meaning real RT source will always be contaminated by significant noise. Thus, clear technologically to an signal RT....

Superconducting quantum circuits are a natural platform for simulations of wide variety important lattice models describing topological phenomena, spanning condensed matter and high-energy physics. One such model is the bosonic analogue well-known fermionic Kitaev chain, 1D tight-binding with both nearest-neighbor hopping pairing terms. Despite being fully Hermitian, chain exhibits number striking features associated non-Hermitian systems, including chiral transport dramatic sensitivity to...