Conveners
AIP: Quantum Science and Technology: QST 2 - Quantum Semiconductors
- Ben Sparkes (Defence Science and Technology Group)
AIP: Quantum Science and Technology: QST 1 - Quantum Computing 1
- Jingbo Wang (The University of Western Australia)
AIP: Quantum Science and Technology: QST 4 - Quantum Optics
- Glenn Solomon (University of Adelaide)
AIP: Quantum Science and Technology: QST 3 - Quantum Computing 2
- Bob Coecke (Quantinuum Ltd.)
AIP: Quantum Science and Technology: QST 6 - Vacancy Centres
- Ben Sparkes (Defence Science and Technology Group)
AIP: Quantum Science and Technology: QST 5 - Quantum Computing 3
- Ben Travaglione (DSTG)
AIP: Quantum Science and Technology: QST 8 - Quantum Computing 4
- Maria Kieferova (University of Technology Sydney)
AIP: Quantum Science and Technology: QST 7 - Quantum Measurement
- Nora Tischler
AIP: Quantum Science and Technology: QST 9 - Quantum Computing 5
- Andrew Doherty (The University of Sydney)
AIP: Quantum Science and Technology: QST 10 - Quantum Communications & Networks 1
- Catalina Curceanu (Istituto Nazionale di Fisica Nucleare)
AIP: Quantum Science and Technology: QST 11 - Quantum Fundamentals 1
- William Munro (NTT Basic Research Laboratories & NTT Research Center for Theoretical Quantum Physics)
AIP: Quantum Science and Technology: QST 13 - Quantum Communications & Networks 2
- Mile Gu (Nanyang Technological University)
AIP: Quantum Science and Technology: QST 12 - Quantum Fundamentals 2
- Gavin Brennen (Macquarie University)
AIP: Quantum Science and Technology: QST 14 - Quantum Fundamentals 3
- Eric Cavalcanti (Griffith University)
AIP: Quantum Science and Technology: QST 15 - Optomechanics
- Alexander Wood (University of Melbourne)
AIP: Quantum Science and Technology: QST 16 - Superconducting Quantum Systems
- Jason Twamley (Quantum Machines Unit, OIST)
AIP: Quantum Science and Technology: QST 17 - Quantum Matter-Light Interactions
- Michael Tobar
Quantum Hall systems are of broad interest as they cover low-dimensional quantum systems, strong charge correlations, and topological physics. Our results lead to a unified understanding of the relaxation processes in graphene over different magnetic field strength regimes.
Our team have performed Quantum Natural Language Processing on an IBM quantum computer and our own trapped-ion hardware. Key to achieving this is the observation that quantum theory and natural language are governed by much of the same compositional structure.
In this work we show the results of an atomistic tight-binding approach coupled with the Non-Equilibrium Green’s Function (NEGF) formalism when applied to phosphorus doped silicon tunnel junctions that can be manufactured with sub-nanometre accuracy.
I would like to apply for a talk (preferred) or poster. I am the primary author of the paper and the one which will present.
Please find attached the abstract in .pdf format.
We build low depth parity check gate set such that these gates become the most natural gate for QEC implementation.By building gates that are fundamental to QEC rather than universal computation,we can boost the threshold and ease the experimental hardness.
This work studies of families of laser models that exhibit both Heisenberg-limited beam coherence, and sub-Poissonian beam photon statistics. In particular, we investigate if imposing sub-Poissonian statistics comes at the expense of a reduction in the coherence.
How to experimentally investigate the fidelity of injected states for error-corrected quantum computing using the surface code and superconducting qubits. The injection method with the highest resultant fidelity minimises the need for resource-intensive state distillation.
We have developed a measurement platform that can report the T1 spin lattice relaxation time from an ensemble of fluorescent nanodiamonds in solution. This platform can be used for rapid material characterisation and chemical sensing in a convenient cuvette-based approach.
We have developed an artificial neural network decoding technique for large scale surface codes with complex boundaries suffering a variety of noise models.
In the practical implementation of relaxometry techniques, systematic errors arise in the quantum state preparation that need to be mitigated for the accurate monitoring of external stimuli. This talk presents strategies to address such limitations for practical applications.
Artificial intelligence is a powerful tool for science, but an important question is how to extract true scientific understanding. We present a method that enables new understanding, and demonstrate its application to quantum photonics.
The immediate prospects of solving real-world problems on near-term Noisy Intermediate Scale Quantum hardware is largely dictated by device noise/errors. We have developed an alternative approach to error mitigation strategies based on quantum computed moments to improve energy/cost function results.
High spin donor atoms are objects of interest in semiconductor quantum architectures due to their large Hilbert space dimensionality. Here we demonstrate high fidelity coherent control over the 16-dimensional Hilbert space of a single 123-Sb atom implanted in silicon.
Gaussian Boson Sampling (GBS) is a prominent model of quantum computing. We experimentally demonstrate both GBS with displacements and with time-bin encoding for the first time. The latter is used to search for dense sub-graphs.
We employ heralded amplification and quantum state teleportation to implement a channel capable that corrects for loss in quantum communication. Our channel genuinely outperforms direct transmission through high amount loss without relying on postselection.
The deterministic implantation of single donors in silicon is realised using ion beam induced charge detectors. This will enable the fabrication of arrays of donor spin qubits, required to scale up the promising quantum computing platform of donors in silicon.
Different methods for compiling analog quantum control pulses for the diamond quantum processor, speed and error benefits of using analog control, and semi-analytical optimisation of analogue control pulses.
Quantum autoencoders use machine learning techniques to compress quantum data and are predicted to be useful for noise mitigation. Our ongoing work aims to experimentally demonstrate denoising of four-dimensional quantum states.
Fast two-qubit phase gates with trapped-ions are feasible with an expected gate fidelity of 77.8% using a sequence of our ultrafast picosecond laser $\pi$-pulses. Such sub-microsecond gate operations support the development of scalable quantum computers.
We discovered a new practical method of perfectly amplifying and teleporting multiphoton light. It is shown to be better than established alternatives. This type of amplifier is useful for a huge variety of quantum technologies.
Nitrogen Vacancies in diamond nanoparticles are employed for in situ monitoring of the magnetic state of photomagnetic materials down to the single particle level, the stability of molecular cages containing atomic Nitrogen, and spin active products of photocatalysis.
Optical quantum computing with continuous variables offers the tantalising promise of room-temperature operation and vast scalability. Here I present an overview of recent key advances in scalability and fault tolerance with this platform.
We measure NMR signals via their modulation of the NV spin-state dependent red photoluminescence intensity using a time-resolved quantum heterodyne detection scheme.
We present the theoretical study of diamond spin maser magnetic field sensor’s limitations considering a detailed photo-physics of the spins. We also present our progress towards the experimental realization of such a sensor.
Cluster states in continuous-variable quantum computing come in various configurations. The authors demonstrated a significant drop in the required quality of a particular configuration. Here, we also present those improvements in other configurations.
We investigate the photo-physics of the nitrogen vacancy centre to improve the optical readout fidelity by designing a new decomposition technique to extract spin state information.
We provide a quantum algorithm for time-dependent differential equations with only logarithmic dependence on the error and derivative. It can be applied to discretised partial differential equations for simulation of classical physics.
We provide a suite of methods to discover the causal model of a quantum process. It is the first complete toolkit for quantum causal discovery, taking into account experimental and computational limitations.
We propose and demonstrate a novel spectroscopy method on donor spin qubit in silicon, which resolves the challenge of low frequency noise estimation with fine resolution
In this work, we introduce a semi-ab initio method for modelling the bound-hole states of the negatively-charged NV center (NV-). Our semi-ab initio approach can be readily adapted to other deep defects in semiconductors.
We analyse the performance of Gottesman Kitaev Preskill quantum error correcting codes during gates and under realistic noise such as loss and dephasing using a new subsystem decomposition.
We are experimentally investigating possible departures from standard quantum mechanics’ predictions at the Gran Sasso underground laboratory in Italy. We are searching for signals predicted by dynamical collapse models, and signals indicating a possible violation of the Pauli Exclusion Principle.
We present a general framework for using quantum error correction codes for protecting and imaging starlight received at distant telescope sites, which can enable long-baseline optical interferometry.
We prove a rigorous form of the adiabatic theorem for a discrete time evolutions. We use this discrete theorem to develop a quantum algorithm for solving linear systems that matches the known lower bound on the complexity of $\kappa$.
Topological data analysis is an important way of understanding features of data, but can be exponentially hard classically. We present new ways of performing topological data analysis on a quantum computer with improved complexity.
We explore how generalisations of the Heisenberg principle arising from modified canonical commutation relations can produce significant effects in recent observations of optomechanical backaction noise, as well as in quantum trajectories of moments derived from general continuous position measurements.
In this talk we will show how a spectral filter, together with a weak Kerr nonlinearity, can be used to tune, and improve, the photon statistics of the spontaneous emission of a strongly-confined exciton-polariton system.
We present techniques, compatible with measurements in digital quantum simulations, for studying critical dynamics in quantum phase transitions, based on the Kibble-Zurek mechanism. In particular, we introduce a sample-and-hold protocol that enables the study of critical exponents in the system.
We discuss the challenges that must be overcome for variational quantum computing to be able to solve chemical systems of more than a few electrons in the context of the variational quantum eigensolver and the quantum computed moments method.
In this work, we examine the assumptions that give rise to barren plateaus in quantum neural networks and show that an unbounded loss function can circumvent the existing no-go results.
Machine learning models are susceptible to adversarial examples - inputs to the model which have been manipulated in order to confuse it. We study the vulnerability and resiliency of quantum classifiers to such inputs.
Inspired by 3D imagining problems we investigate methods of quantum encodings that are invariant to permutations of points in the original input for collections of 3D points (point cloud) data, within the context of a particle physics application.
We present a method – genetic algorithm for state preparation (GASP) – which generates low-depth quantum circuits for initialising a quantum computer in a specified quantum state.
Talk based on a combination of Phys. Rev. X 12, 011007 and unpublished work.
In a thermal-loss channel, it is uncertain whether a discrete-variable or a continuous-variable quantum key distribution (QKD) protocol is more optimal. We investigate QKD protocols in a thermal-loss setting but with the assumed availability of perfect sources and detectors.
Discrete modulated continuous variable quantum key distribution (CVQKD) performs better than Gaussian modulated CVQKD in low signal-to-noise-ratio (SNR) regimes. We present results on the study of its performance in a satellite-to-ground context in the asymptotic and finite-size limit.
We demonstrate a truly reference-frame-independent quantum key distribution protocol utilising a 4-photon entangled state. We present our latest results showing how local and global rotational invariance makes this protocol immune to a jamming attack.
Certified quantum randomness protocols can securely guarantee random numbers that are unpredictable to any physical observer. We experimentally implement one such protocol based on quantum steering using single photons.
I’ll describe protocols for simplified quantum processing on qubits using interactions mediated by quantized bosonic modes. These have applications for error mitigated quantum sensing and for non-local gates for low overhead quantum error correction.
We apply the wavelet transform to generate compressed representations of ground states of QFTs and demonstrate applications such as identification of quantum phase transitions via fidelity overlap and approximation of the holographic entanglement of purification.
Hidden variable models that attempt to ascribe objective notion of being particle or wave contradict experiments. Quantum-controlled delayed choice experiments may show that they are internally inconsistent, and use of, entanglement makes them impossible to define.
We establish universal performance bounds pertaining to the general quantum error mitigation protocols. We employ them to show the fundamental difficulty of mitigating noise in variational quantum circuits and the optimality of the probabilistic error cancellation method.
We predict violations of Bell, Leggett-Garg, and dimension-witness inequalities for macroscopic qubits based on macroscopically-distinct coherent states. This challenges our understanding of macroscopic realism versus quantum mechanics and motivates the examination of realism in quantum mechanics.
We analyse the ontological models framework underlying Spekkens' formalism for contextuality, in the light of quantum causal models. We argue that QCMs can maintain the spirit of noncontextuality by rejecting classical assumptions about how intermediate causes screen off correlations.
The inherent differences between classical quantum physics means it is essential for us to establish how a quantum internet will operate, including the functionality required from quantum repeaters as well as the support our telecommunications internet will need to provide.
Nonlocality is a paramount resource for quantum communications. In this experimental work, we aim to demonstrate, using single photons, the emergence of Bell nonlocality in quantum states that would be unable to display nonclassical behaviour in the standard Bell scenario.
In this talk, we present universal performance behaviours in Trotterised digital quantum simulations. For example, beyond a threshold in Trotter step size, the Trotterisation performance breakdown with the onset of quantum chaos, meaning the Trotterised unitary becomes a random matrix.
In this work we formally define the retrofiltered quantum state using the quantum state smoothing formalism and Bayesian estimation theory. Additionally, we are able to define a total of 9 different estimators using this framework, of which 3 are novel.
We designed a quantum optical version of time delayed self-sustained oscillations, which has focused towards developing quantum clocks.
See Abstract Attached
Quantum nonlocality is a resource that enables secure quantum information tasks. Steering nonlocality is a scenario where one party is in a secure location and another party is not. Here, we show detection-loophole-free quantum steering, using a vector-vortex state encoding.
The highest rates of quantum communication networks are fundamentally limited by the transmission distance between quantum repeaters. In this work, we give a practical design for this achievability.
We realise a common principle that applies to a wide range of seemingly distinct concepts and diagnostics of quantum chaos. We use this to identify a fundamental link between quantum chaos and entanglement.
We develop and demonstrate a set of tools for both detailed and efficient characterisation of the full set of temporal correlations present in quantum dynamics. Applications range from noise reduction to the general study of open quantum systems.
Studying the correlations within a bipartite sequential Wigner's friend experiment, in particular when compared to the already known correlations of a scenario with the same number of inputs and outputs under a local hidden variable model.
We compute states that maximize average fidelity over ensembles of quantum states via semidefinite programs. We derive lower and upper bounds to maximal average fidelity that are exact in the commuting scenario. Our results find applications in tomography.
The Quantum Computed Moments (QCM) method offers a powerful correction to the ground state energy estimate obtained in variational quantum algorithms. We observe that this QCM estimate is incredibly robust to noise, and analyse the versatility of the approach.
We introduce a new method to simulate the dynamics of an open quantum system by using a hierarchy of master equations, which update not only the relevant information about the system but also the leading correlations of the bath operators.
I will discuss the advantages of magnetic trapping for trapping and cooling of nano-micron-scaled objects. This complete passive type of trap heralds the potential for low noise levitation and the creation of ultrahigh-motional-Q massive oscillators.
We demonstrate rapid quantum control of optically-dark nuclear spins in diamond, which are typically isolated from both magnetic noise and oscillating control fields, through magnetic-field induced augmentation.
We present novel quantum frameworks for inferring the quantum state of the mechanical oscillator in different scenarios and elaborate on how they are applied to a resonator in the lab.
The presented work demonstrates the cooling of an X-band microwave mode with an ensemble of hyper-polarised room temperature nitrogen vacancy centres in diamond.
Nitrogen-Vacancy centres in diamond are promising room-temperature quantum sensors. However, interaction with bath-spins in the surrounding lattice can lead to strong decoherence. We investigate decoupling of these interactions by driving the bath-spins with chirped signals.
This work includes: 1) Our study and application of putative modified physical equations due to beyond-standard-model physics, to determine possible new experiments; 2) An overview of our current experimental program, including status and future directions.
We report the first realisation of a passive on-chip circulator which is made from a superconducting loop with three Josephson junctions and is tuned with only DC control fields. Our results demosntrated non-reciprocal behaviour and identified future path for improvement.
As quantum processors begin to scale, optimising the cryogenic wiring for superconducting quantum devices is becoming an important challenge for developing powerful quantum computers. This work tackles this problem for industry-scale devices and identifies new avenues for improving qubit capacities.
In this work, we introduce new "adiabatic" techniques for implementing Jaynes-Cummings qubit-cavity interactions that enable low-bandwidth, ultrashort effective Jaynes-Cummings pulses. We demonstrate tunable positive- and negative-time Jaynes-Cummings gates with >99% fidelity for up to 100 sequential gates.
Squeezing electromagnetic noise allows for measurements beyond the standard quantum limit relevant to a range of quantum applications. Here we present the first results in realising direct noise squeezing with a kinetic inductance parametric amplifier.
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Quantum sensors exhibit promising real-world applications of quantum mechanics that exploit its most counterintuitive properties. I present an ongoing project that aims to design, build, and test a new type of quantum rotation sensor, the vortex matterwave gyroscope.
We implement experimentally a paradigmatic model of a quantum battery, constructed of a microcavity enclosing a molecular dye.
The first steps towards a proof-of-concept memory powered heat engine using trapped $^{171}$Yb$^+$ ions. This proof-of-concept intends on showing entropy transfer between thermal and spin reservoirs with minimal energy loss, therefore allowing a higher efficiency heat engine than allowed classically.
