Quantum computational models can be approached via the lens of resources needed to perform computational tasks, where a computational advantage is achieved by consuming specific forms of quantum resources, or, conversely, resource-free computations are classically simulable. Can we similarly identify quantum computational resources in the setting of more general quasi-particle statistics? In this work, we develop a framework to characterize the separability of a specific type of one-dimensional quasiparticle known as a fermionic anyon. As we evince, the usual notion of partial trace fails in this scenario, so we build the notion of separability through a fractional Jordan-Wigner transformation, leading to an entanglement description of fermionic-anyon states. We apply this notion of fermionic-anyon separability and the unitary operations that preserve it, mapping it to the free resources of matchgate circuits. We also identify how entanglement between two qubits encoded in a dual-rail manner, as standard for matchgate circuits, corresponds to the notion of entanglement between fermionic anyons.

Microwave-driven logic is a promising alternative to laser control in scaling trapped-ion based quantum processors. We implement Mølmer-Sørensen two-qubit gates on ${}^{43}{\mathrm{Ca}}^{+}$ hyperfine clock qubits in a cryogenic $(\approx 25 \mathrm{K})$ surface trap, driven by near-field microwaves. We achieve gate durations of 154 µs [with 1.0(2)% error] and 331 µs [0.5(1)% error], which approaches the performance of typical laser-driven gates. In the 331 µs gate, we demonstrate a Walsh-modulated dynamical decoupling scheme which suppresses errors due to fluctuations in the qubit frequency as well as imperfections in the decoupling drive itself.

We study the self-testing problem of quantum correlations in the context of a multipartite scenario, a task that becomes increasingly complex compared to the bipartite systems. Recently, [Šupić et al., Nat. Phys. 19, 670 (2023)] introduced a novel self-testing method for pure multipartite entangled states, which leverages network assistance and relies on bipartite entangled measurements. Hence, their scheme loses the ideal device-independent nature of self-testing. To address this, we provide a self-testing scheme for genuine multipartite entanglement in the true sense. Our approach utilizes a generalized Hardy-type nonlocality argument and requires only local operations, eliminating the need for network assistance or bipartite entangled measurements. Furthermore, we establish a device-independent bound for the maximum probability of success for a generalized Hardy-type argument. This paves the way for reliable and efficient self-testing of quantum correlations without relying on additional resources.

We present a faithful geometric picture for genuine tripartite entanglement of discrete, continuous, and hybrid quantum systems. We first find that the triangle relation ${\mathcal{E}}_{i|jk}^{\alpha }\le {\mathcal{E}}_{j|ik}^{\alpha }+{\mathcal{E}}_{k|ij}^{\alpha }$ holds for all subadditive bipartite entanglement measure $\mathcal{E}$, all permutations under parties $i,j,k$, all $\alpha \in [0,1]$, and all pure tripartite states. Then, we rigorously prove that the nonobtuse triangle area, enclosed by side ${\mathcal{E}}^{\alpha }$ with $0<\alpha \le 1/2$, is a measure for genuine tripartite entanglement. Finally, it is significantly strengthened for qubits that given a set of subadditive and nonsubadditive measures, some state is always found to violate the triangle relation for any $\alpha >1$, and the triangle area is not a measure for any $\alpha >1/2$. Our results pave the way to study discrete and continuous multipartite entanglement within a unified framework.

We demonstrate a spin-precession method to observe and analyze multilevel coherence between all hyperfine levels in the $X{}^2{\mathrm{\Sigma }}^{+},N=0$ ground state of barium monofluoride (${}^{138}\mathrm{Ba}{}^{19}\mathrm{F}$). The signal is sensitive to the state-preparation Rabi frequency and external electric and magnetic fields applied in searches for a permanent electric dipole moment (EDM). In the obtained interference spectrum, the electric field and Rabi frequency become observable simultaneously with the EDM. This method reduces systematic biases and the number of auxiliary measurements for such precision measurements.

We study the phase matching of resonant high-harmonic generation (HHG) and high-order frequency mixing (HFM) in plasma. We numerically solve the propagation equations coupled with the time-dependent Schrödinger equation for the nonlinear polarization. The macroscopic harmonic signal is enhanced in the vicinity of a multiphoton resonance with the transition between the ground and autoionizing states of the generating ion. We show that narrow and strong resonances (as for gallium and indium ions) provide compensation of the plasma dispersion in a spectral region above the exact resonance, improving the phase matching and leading to a high macroscopic signal. The compensation does not take place for a wider resonance (as for manganese ions), instead the phase matching is achieved in the HFM process. Comparing the XUV generated in manganese plasma and in neon gas, we show that the resonant HHG in plasma is an order of magnitude more effective than in the gas; moreover, another order of magnitude can be gained from the propagation using HFM in plasma.

We introduce prethermal temperature probes for sensitive, fast, and robust temperature estimation. While equilibrium thermal probes with a manifold of quasidegenerate excited states have been previously recognized for their maximal sensitivity, they suffer from long thermalization timescales. When considering time as a critical resource in thermometry, it becomes evident that these equilibrium probes fall short of ideal performance. Here, we propose a different paradigm for thermometry, where setups originally suggested for optimal equilibrium thermometry should instead be employed as prethermal probes, by making use of their long-lived quasiequilibrium state. This transient state emerges from the buildup of quantum coherences among quasidegenerate levels. For a class of physically motivated initial conditions, we find that energy measurements of the prethermal state exhibit a similar sensitivity as the equilibrium state. However, they offer the distinct benefit of orders of magnitude reduction in the time required for the estimation protocol. Upon introducing a figure of merit that accounts for the estimation protocol time, prethermal probes surpass the corresponding equilibrium probes in terms of effective thermal sensitivity, opening avenues for rapid thermometry by harnessing the long-lived prethermal states.

Coherent control has enabled various novel phenomena in wave scattering. We introduce an effect called coherent orthogonal scattering, where the output wave becomes orthogonal to the reference output state without scatterers. This effect leads to a unity extinction coefficient and complete mode conversion. We examine the conditions for this effect and reveal its topological nature by relating it to the indivisibility between the dimension and the winding number of scattering submatrices. These findings deepen our understanding of topological scattering phenomena.

We study the nonequilibrium dynamics of a quantum spin-1/2 $XXZ$ model confined in a two-dimensional bilayer system, with couplings mediated by inverse power-law interactions, falling off with distance $r$ as $1/r^{\alpha }$, with spatiotemporal control of the spins enabled via local fields. An initial state of spins with opposite magnetization in the two layers is dynamically unstable resulting in exponential generation of correlated pairs of excitations. We find that scalable generation of entanglement in the form of two-mode squeezing between the layers can generically be achieved in power-law models. We further demonstrate that spatially temporally engineered interactions allow one to significantly increase the generated entanglement and in fact achieve Heisenberg limited scaling. This work is relevant to a wide variety of experimental atomic, molecular, and optical platforms, which realize power-law spin models, and demonstrates the advantage of spatiotemporal control to maximize the generation of metrologically useful entanglement, with potential applications in quantum-enhanced sensing.

We show that the precise microwave preparation of a quantum superposition between three rotational states of an ultracold dipolar molecule generates controllable interferences in their two-body scattering dynamics and collisional rate coefficients, at an electric field that produces a Förster resonance. This proposal represents a feasible protocol to achieve coherent control on ultracold molecular collisions in current experiments. It sets the basis for future studies in which one can think to control the amount of each produced pairs, including trapped entangled pairs of reactants, individual pairs of products in a chemical reaction, and measuring each of their scattering phase shifts that could envision “complete chemical experiments” at ultracold temperatures.

This Letter studies the symmetry properties of general vector correlations resulting from one-photon excitation of chiral molecules. We show that the parity-odd second rank tensor is nonzero for molecules in all chiral point groups $C_n, D_n, T, O$, and $I$. This chirality-sensitive tensor is nonzero even for chiral isotopomers excited by linearly polarized or even unpolarized light. We develop an irreducible tensor theory based on Curie's limiting groups. As an example of vector correlations, recoil-frame photoelectron angular distributions (RFPADs) are calculated for methyloxirane and $\mathrm{CHF}{}^{35}\mathrm{Cl}{}^{37}\mathrm{Cl}$. The difference in the RFPAD between a chiral molecule and its mirror image reaches $\pm 35$% of the maximum value for the RFPAD for unpolarized light and $\pm 55$% of the value for linearly polarized light. Chiral sensitivity in vector correlation is a quite general phenomenon arising from one-photon excitation by unpolarized and linearly polarized light, and we expect it to be of great importance in time-resolved spectroscopy of ultrafast chemical reactions.

We study density isolines in quantum turbulence under the Schramm-Loewner framework using direct numerical simulations of the truncated Gross-Pitaevskii equation, in both spherical and cylindrical traps with three-dimensional dynamics. Density isolines develop increasing complexity as turbulence matures. As the systems evolves towards a thermalized regime, it spontaneously develops conformal invariance. In contrast to other systems exhibiting conformal invariance, this system manifests it during the transition towards disorder rather than to self-organization. We discuss a link between this behavior in quantum turbulence and other four-wave interacting systems.

As an essential component of state-of-the-art quantum technologies, fast and efficient quantum measurements are in persistent demand over time. Here, we present a precision measurement scheme for weak signals. We propose a dimensionless pseudo-spin pointer based on weak measurement which effectively converts a continuous measurement into a discrete one. We demonstrate experimentally that a weak perturbation of the parametric distribution's moment can be retrieved efficiently by employing the pointer without measuring the distribution literally. The results show that for signals three to four orders weaker in strength than the area-array camera method, an order of improvement in precision is achieved experimentally. We expect that this method can be effectively loaded into various quantum systems and promote the development of quantum precision measurement or quantum computing.

We investigate the exact solvability and point-gap topological phase transitions in non-Hermitian lattice models. These models incorporate site-dependent nonreciprocal hoppings $J{e}^{\pm g_n}$, facilitated by a spatially fluctuating imaginary gauge field $i{g}_n\widehat{x}$ that disrupts translational symmetry. By employing suitable imaginary gauge transformations, it is revealed that a lattice characterized by any given $g_n$ is spectrally equivalent to a lattice devoid of fields, under open boundary conditions. Furthermore, a system with closed boundaries can be simplified to a spectrally equivalent lattice featuring a uniform mean field $i\overline{g}\widehat{x}$. This framework offers a comprehensive method for analytically predicting spectral topological invariance and associated boundary localization phenomena for bond-disordered nonperiodic lattices, based on gauge-transformed isospectral periodic lattices. Notably, for a lattice with quasiperiodic $g_n=ln|\lambda cos2\pi \alpha n|$ and an irrational $\alpha$, a previously unknown topological phase transition is unveiled. It is observed that the topological spectral index $W$ assumes values of $-N$ or $+N$, leading to all $N$ open-boundary eigenstates localizing either at the right or left edge, solely dependent on the strength of the gauge field, where $\lambda <2$ or $\lambda >2$. A phase transition is identified at the critical point $\lambda \approx 2$, at which all eigenstates undergo delocalization. The theory has been shown to be relevant for long-range hopping models and for higher dimensions.

The structure of self-bound one-dimensional droplets containing a mixture of ytterbium fermionic isotopes $({}^{173}\mathrm{Yb},$ ${}^{171}\mathrm{Yb})$ is calculated by means of a diffusion Monte Carlo technique. We considered only balanced setups in which all the atoms of one isotope are spin polarized, while the atoms of the other can have up to three different spin values. Our results indicate that these droplets consist of consecutive “molecules” made up of one ${}^{173}\mathrm{Yb}$ and one ${}^{171}\mathrm{Yb}$ atom. The fermionic nature of those Yb atoms makes pairs with identical spin composition avoid each other, producing an effective antiferromagnetic coupling between different kinds of composite bosons. This antiferromagnetism is different than the one induced by an external optical lattice potential within the framework of the Hubbard model reported in previous literature, and different from the standard ferromagnetic behavior typical of bosonic arrangements.

We present a theoretical description of resonant charge transfer in collisions of nanoparticles, specifically for ${\text{C}}_{60}+{\text{C}}_{60}^{+}$ collisions. We predict that transient bonds between colliding fullerenes can significantly extend the interaction time, allowing for a greater probability of charge transfer. In our model, the dumbbell-shaped ${({\text{C}}_{60}-{\text{C}}_{60})}^{+}$ quasimolecule, that is temporarily formed during the collision, is described as a dynamic system of 120 zero-range potentials. Using this model, we calculate the exchange interaction between colliding fullerenes and subsequently determine the corresponding charge-transfer cross sections at different collision velocities. Our results have been verified with data obtained from quantum molecular dynamics simulations of the fullerene collisions. The presented theoretical model provides a description of the experimental data on the ${\text{C}}_{60}+{\text{C}}_{60}^{+}$ resonant charge-transfer collision through the inclusion of the temporary formation of dumbbell-shaped fullerene molecules at low collision velocities.

We discuss a generalization of the non-Hermitian skin effect to finite-size photonic structures with neither gain nor loss in the bulk and a purely real energy spectrum under periodic boundary conditions (PBCs). We show that despite being Hermitian in the bulk, such systems can still have significant portions of eigenmodes concentrated at the edges and that this edge concentration can be linked to the nontrivial point-gap topology of the size-dependent regularized PBC spectrum, accounting for the radiative losses due to photon emission through the edges. We focus on a particular example of an array of atoms chirally coupled to the waveguide, but our results are also applicable to other systems with losses through the edges.

The long-range spatial and temporal ordering displayed by discrete time crystals, can become advantageous properties when used for sensing extremely weak signals. Here, we investigate their performance as quantum sensors of weak ac fields and demonstrate, using the quantum Fisher information measure, that they can overcome the shot-noise limit while allowing long interrogation times. In such systems, collective interactions stabilize their dynamics against noise, making them robust enough to protocol imperfections.

We show that the performance of critical quantum metrology protocols, counterintuitively, can be enhanced by finite temperature. We consider a toy-model squeezing Hamiltonian, the Lipkin-Meshkov-Glick model, and the paradigmatic Ising model. We show that the temperature enhancement of the quantum Fisher information can be achieved by adiabatic preparation of the state close to the critical point and by preparing it directly in the proximity of the critical point. We also find a relatively simple, however, nonoptimal measurement capable of harnessing finite temperature to increase the parameter estimation sensitivity. Therefore, we argue that temperature can be considered as a resource in critical quantum metrology.

The first passage time (FPT) is the time taken for a stochastic process to reach a desired threshold. In this Letter we address the FPT of the stochastic measurement current in the case of continuously measured quantum systems. We find that our approach, based on a charge-resolved master equation related to full-counting statistics of charge detection, enables efficient and analytical computation of the FPT. We develop a versatile framework applicable to quantum jump unraveling and quantum diffusion scenarios, demonstrating that the FPT can be obtained by introducing absorbing boundary conditions. Our framework is demonstrated with two relevant examples: First, we examine the tightness of recently proposed kinetic uncertainty relations for quantum jumps, which place bounds on the signal-to-noise ratio of the FPT. Second, we investigate the usage of qubits as threshold detectors for Rabi pulses, showing how our method can optimize detection probability while minimizing false positives. This Letter offers insights into the applications of the FPT for continuous measurements including the signal-to-noise ratio bounds and false positive minimization strategies, advancing quantum information processing applications.