Chronological feed of everything captured from Mikhail Lukin.
paper / mikhaillukin / Apr 29
Researchers introduce fault-tolerant compilation for degree-D IQP circuits using [[2^D, D, 2]] error-detecting codes on reconfigurable neutral atom arrays in hypercube geometry. These codes support transversal and permutation gates for arbitrary IQP realization with native hardware operations, matching recent Bluvstein et al. experiments. They prove classical intractability for Bell sampling from degree-4 IQP circuits and develop scalable [[O(d^D), D, d]] color codes for exponential error suppression.
quantum-error-correctionfault-tolerant-quantumiqp-circuitsneutral-atom-arrayhypercube-geometryquantum-samplingcomputational-hardness
“[[2^D, D, 2]] quantum error detecting codes realize arbitrary degree-D IQP circuits via transversal and permutation gates.”
paper / mikhaillukin / Apr 29
Researchers demonstrate Floquet engineering with microwave pulses to realize XXZ and XYZ spin models in ultracold KRb polar molecules confined in optical lattices, validated against DC electric field tuning via Ramsey contrast dynamics. They observe two-axis twisting mean-field dynamics using a Floquet-engineered XYZ Hamiltonian with itinerant molecules in 2D layers. This approach accesses Hamiltonians beyond static fields, enabling entangled states for precision measurement and multi-level quantum simulation.
floquet-engineeringpolar-moleculestwo-axis-twistingxyz-spin-modelsquantum-many-bodyultracold-moleculesquantum-simulation
“Floquet microwave pulse sequences tune XXZ spin models in KRb molecules equivalently to DC electric fields”
paper / mikhaillukin / Mar 5
Correlated decoding jointly processes errors across logical qubits to account for propagation during transversal entangling gates, boosting performance in both Clifford and non-Clifford cases. For Clifford circuits, it exploits deterministic stabilizer error propagation to cut noisy syndrome extraction rounds from O(d) to O(1), where d is code distance. Numerical validation shows substantial space-time cost reductions for deep logical Clifford circuits, aiding early fault-tolerant quantum computation.
quantum-error-correctiontransversal-gatescorrelated-decodinglogical-qubitsquantum-computationstabilizer-codesfault-tolerant-computing
“Correlated decoding improves performance of logical algorithms using transversal entangling gates”
paper / mikhaillukin / Mar 2
Researchers observe a hydrodynamic magnon sound mode in atomically thin CrCl3 using NV center quantum coherence to probe thermal magnetic fluctuations. Anomalous temperature dependence—fluctuations increasing as temperature decreases—arises from sharpening damping of the low-energy collective mode due to enhanced magnon interactions. Spectroscopic evidence confirms the 2D magnon sound mode via driven multilayer measurements.
magnon-hydrodynamicsatomically-thin-ferromagnetspin-wavescollective-excitationsnv-centers2d-magnonscondensed-matter-physics
“Thermal magnetic fluctuations from monolayer CrCl3 increase upon decreasing temperature.”
paper / mikhaillukin / Jan 24
Researchers develop an efficiently implementable MERA tensor network model mapping a (1+1)D critical spin system to a (2+1)D bulk theory, simulating AdS/CFT duality. Numerical and analytical results reveal bulk excitations with attractive interactions, where one- and two-particle energies match AdS gravity predictions at long distances. These holographic forces emerge directly from entanglement renormalization, enabling efficient simulation of bulk dynamics on quantum devices.
ads-cfttensor-networksholographyquantum-gravitymeraquantum-simulationcriticality
“MERA tensor network provides a mapping between a (1+1)-dimensional critical spin system and a (2+1)-dimensional bulk theory simulating AdS/CFT.”
paper / mikhaillukin / Dec 12
Polarization gradient cooling (PGC) in a corrugated micrometer-sized optical dipole trap produces a small Bose-Einstein condensate of ~250 87Rb atoms without evaporative cooling. Machine learning optimization increased atom number by 5x and decreased temperature by 2.5x, yielding nearly two orders of magnitude gain in phase space density. BEC forms in a local dimple due to slight misalignment of trapping light through a microscopic objective, within 40 ms of PGC.
bose-einstein-condensatepolarization-gradient-coolinglaser-coolingquantum-gasesatomic-physicsmachine-learning-optimization
“PGC alone generates a Bose-Einstein condensate of ~250 87Rb atoms”
paper / mikhaillukin / Dec 7
Researchers demonstrate a programmable quantum processor using reconfigurable neutral atom arrays with up to 280 physical qubits encoding logical qubits. The system supports high-fidelity two-qubit gates, arbitrary connectivity, mid-circuit readout, and various encodings like surface code (d=3 to d=7), color codes, and 3D [[8,3,2]] codes. They achieve fault-tolerant operations including GHZ state creation, entanglement teleportation, and complex sampling circuits with 48 logical qubits, 228 logical CNOTs, and 48 CCZ gates, outperforming physical qubits in error-detected algorithmic tasks.
quantum-processorlogical-qubitsneutral-atom-arraysquantum-error-correctionsurface-codecolor-codearxiv-paper
“Processor operates with up to 280 physical qubits encoding logical qubits”
paper / mikhaillukin / Dec 4
The framework uses reconfigurable qubit architectures to simulate real-time dynamics of strongly correlated quantum systems via model spin Hamiltonians. It employs digital-analog simulation with Floquet engineering and multi-qubit operations for accurate spin-spin interactions, exemplified on Rydberg atom arrays. Classical co-processing of quantum measurements extracts spectral properties like excitation energies and susceptibilities from single datasets via snapshot measurements and ancilla control.
quantum-simulationquantum-processorsspin-hamiltoniansquantum-chemistryrydberg-atomsspectral-propertiesquantum-materials
“Simulation framework targets strongly correlated quantum systems representable by model spin Hamiltonians”
paper / mikhaillukin / Nov 29
Researchers observe a microemulsion phase between Wigner crystal and electron liquid in a MoSe2 monolayer using cryogenic reflectance and magneto-optical spectroscopy. The transition shows anomalies in exciton reflectance, spin susceptibility, and Umklapp scattering, confirming a distinct mixed state. This self-organized phase arises from competing quantum ground states under strong Coulomb interactions in 2D systems.
wigner-crystalelectronic-microemulsionquantum-phase-transitionstrongly-correlated-electrons2d-materialsmo-se2-monolayercondensed-matter-physics
“A microemulsion phase emerges between electronic Wigner crystal and electron liquid in MoSe2 monolayer.”
paper / mikhaillukin / Nov 21
Researchers use electrostatic gates in atomically thin heterostructures to trap interlayer excitons (IEs) and achieve densities exceeding 2×10¹² cm⁻² via Stark shift modulation. At high densities, linewidth broadening indicates an IE ionization transition that is independent of trap depth. This threshold persists at low temperatures but rises above 20 K, aligning with quantum dissociation in a degenerate IE gas, advancing dipolar exciton condensate realization.
interlayer-excitonsexciton-ionization2d-heterostructureselectrostatic-trapmesoscale-physicsnanoscale-physicsstrongly-correlated-electrons
“Electron-hole pair concentrations above 2×10¹² cm⁻² are achieved by electrically modulating the IE Stark shift.”
paper / mikhaillukin / Oct 2
Researchers demonstrate a two-node quantum network using SiV centers in nanophotonic diamond cavities, achieving remote entanglement via cavity-enhanced spin-photon interactions and heralded time-bin gates. Nuclear spins provide second-long entanglement storage with integrated error detection, connected through bi-directional quantum frequency conversion to 1350 nm telecom wavelengths. Entanglement is realized over 40 km fiber spools and a 35 km urban Boston fiber loop, advancing quantum repeaters.
quantum-networksnanophotonic-quantum-memorytelecom-fiber-entanglementsilicon-vacancy-centersquantum-repeatersspin-photon-entanglement
“Two-node quantum network uses SiV electron and nuclear spins in diamond nanocavities for entanglement via telecom fiber.”
paper / mikhaillukin / Sep 13
Researchers integrate high-stress silicon nitride thin films with diamond nanostructures to reproducibly induce static strain (~4×10^{-4}) in silicon-vacancy (SiV) color centers, achieving a mean ground state splitting of 608 GHz. This strain suppresses phonon-mediated decoherence, enabling operation beyond 1 K and potentially up to 1.5 K without spin property degradation, as supported by modeling. The technique provides a scalable, generalizable method for high-temperature quantum memories applicable to other color center platforms.
color-centerssilicon-vacancystrained-qubitsdiamond-nanostructuresquantum-memorieshigh-stress-thin-films
“Unstrained silicon-vacancy centers in diamond require millikelvin temperatures for long coherence properties.”
paper / mikhaillukin / Aug 30
Local electromagnetic noise spectroscopy is proposed as a noninvasive method to probe Wigner crystal phases in strongly interacting 2D electron systems. At probe-sample distances below inter-electron spacing, it achieves single-site resolution for in-plane electron crystal imaging. At larger distances, it reveals low-energy phonon properties including transverse shear mode dispersion, disorder-induced pinning resonances, and optical modes in bilayer crystals, aiding analysis near melting transitions.
wigner-crystalsnoise-spectroscopytwo-dimensional-materialsstrongly-correlated-electronscondensed-matter-physicsarxiv-paper
“Local noise spectroscopy provides single-site resolution of the electron crystal when sample-probe distance is less than inter-electron separation.”
paper / mikhaillukin / Aug 16
qLDPC codes achieve high encoding rates and good distance scaling for low-overhead fault-tolerant quantum computing but require long-range connectivity. A hardware-efficient scheme uses atom rearrangement in reconfigurable atom arrays to implement non-local syndrome extraction with constant overhead, leveraging the product structure of qLDPC codes. Circuit-level simulations show this architecture outperforms surface codes with several hundred physical qubits at 10^{-3} error rates, achieving over an order of magnitude qubit savings with under 3000 qubits and supporting thousands of logical qubits with less than 10^5 physical qubits.
qldpc-codesfault-tolerant-quantumatom-arraysquantum-computingsurface-codereconfigurable-qubits
“qLDPC-based architecture with reconfigurable atom arrays achieves effectively constant overhead in syndrome extraction for fault-tolerant quantum computation.”
paper / mikhaillukin / Aug 4
Rydberg atom array quantum simulators provide imperfect projective measurement data that enhances variational Monte Carlo (VMC) simulations of quantum matter. By integrating this data into training of autoregressive RNN wavefunction ansätze, convergence times improve universally for a 16x16 lattice spanning disordered-to-checkerboard phase transition. Pre-training with experimental data enables simple RNNs to capture phases inaccessible via purely variational methods, advancing hybrid quantum-classical simulation scalability.
quantum-simulationrydberg-atomsvariational-monte-carloneural-network-wavefunctionsquantum-many-bodyhybrid-quantum-classical
“Unprocessed experimental projective measurement data from Rydberg arrays improves VMC simulation performance.”
paper / mikhaillukin / Jul 28
Researchers developed and characterized a 50-km telecom fiber quantum network testbed in the Boston area, dubbed BARQNET, measuring time-of-flight, polarization, and phase noise on quantum signals. They designed a compensation system resilient to these impairments and compatible with quantum memory integration. These advances enable near-term quantum networking demos and guide technology development for scalable systems.
quantum-networkingfiber-opticsquantum-communicationtestbednoise-compensationquantum-physicsbarqnet
“BARQNET is a 50-km fiber quantum network testbed in the Boston area.”
paper / mikhaillukin / Jul 17
Researchers demonstrate bidirectional quantum frequency conversion between visible-band single photons from a silicon-vacancy (SiV) center in diamond and telecom O-band, achieving g²(0) < 0.1 noise and 89 ± 8% indistinguishability. They further map telecom time-bin qubits transmitted over a 50 km deployed fiber link onto the SiV memory with 87 ± 2.5% fidelity. This enables direct integration of solid-state diamond quantum memories into telecom-band quantum networks.
quantum-networkingdiamond-quantum-memoryquantum-frequency-conversionsilicon-vacancytelecom-bandquantum-repeatersarxiv-paper
“Conversion of visible-band single photons from SiV center to telecom O-band maintains g²(0) < 0.1”
paper / mikhaillukin / Jun 22
Quantum adiabatic optimization for maximum independent set on Rydberg atom arrays faces superexponential runtime due to vanishingly small minimum gaps from locally independent choices that trap the system in suboptimal configurations. These gaps decay superexponentially with system size, leading to Hamming-distant states from the ground state. Quantum quenches from suboptimal configurations leverage many-body scar signatures to achieve larger ground state overlap, circumventing the runtime bottleneck.
quantum-adiabatic-optimizationsuperexponential-runtimesmaximum-independent-setrydberg-atom-arrayquantum-many-body-scarsquantum-quenches
“Minimum gap in adiabatic evolution for certain maximum independent set instances on Rydberg arrays decays superexponentially with system size”
paper / mikhaillukin / Jun 22
Optimized quantum adiabatic algorithms yield quadratic speedups over classical MCMC on Maximum Independent Set problems with flat low-energy landscapes, as motivated by Ebadi et al.'s experimental superlinear speedup on unit-disk graphs. A theoretical framework compares these to broad classical MCMC classes, identifying conditions for quantum advantage or slowdown on hard instances. Adding a sign-problem-free local Hamiltonian enables quadratic speedup against simulated annealing, parallel tempering, and quantum Monte Carlo.
quantum-speedupadiabatic-algorithmcombinatorial-optimizationquantum-algorithmsmarkov-chain-monte-carloindependent-setflat-energy-landscapes
“Quantum adiabatic algorithm achieves quadratic speedup over classical MCMC on hard MIS instances with flat low-energy landscapes”
paper / mikhaillukin / Jun 16
Researchers demonstrate a reproducible cryogenic packaging technique coupling tapered optical fibers to nanophotonic devices with <1 dB loss per facet at ~730 nm, stable from 300 K to 30 mK. The method enables permanent, broadband interfaces compatible with etched lithium niobate on insulator waveguides. This addresses scattering losses, enabling scalable photonic integration for classical and quantum applications at room and cryogenic temperatures.
nanophotonicscryogenic-packaginglow-loss-couplingoptical-fiberslithium-niobatequantum-photonics
“Coupling loss between tapered optical fiber and nanophotonic devices is <1 dB per facet at ~730 nm”
paper / mikhaillukin / Jun 6
Dynamically field-programmable qubit arrays (DPQA) enable qubit transport and reconfigurable entangling operations across non-local pairs in neutral atom processors. The OLSQ-DPQA compiler models layout synthesis as a satisfiability modulo theories (SMT) problem for optimal circuit depth, supplemented by a greedy peeling heuristic for scalability. On benchmarks, it reduces two-qubit gates 1.7x versus fixed planar layouts on small instances and achieves 5.1x fewer gates for 90-qubit circuits versus grid architectures.
quantum-compilationneutral-atomsdpqaqubit-routingquantum-circuitslayout-synthesisquantum-algorithms
“OLSQ-DPQA compiler reduces two-qubit entangling gates by 1.7x compared to optimal fixed planar architecture on small benchmark instances.”
paper / mikhaillukin / May 16
Researchers introduce a geometric formalism for designing robust pulse sequences in strongly interacting qudit systems, simplifying dynamical decoupling and Hamiltonian engineering while ensuring robustness. Demonstrated experimentally in disordered spin-1 NV center ensembles, it achieves over 10x coherence time improvement versus prior sequences. The approach enables engineering quantum many-body scars and enhances quantum metrology sensitivities by realizing complex qudit Hamiltonians.
quantum-physicsqudit-systemshamiltonian-engineeringdynamical-decouplingquantum-metrologymany-body-physicsnv-centers
“Geometric formalism simplifies qudit pulse sequence design with robustness conditions”
paper / mikhaillukin / May 15
Discrete time crystals emerge from spontaneous breaking of time translation symmetry, manifesting rigid subharmonic oscillations via many-body interactions, collective synchronization, and ergodicity breaking. The review emphasizes ergodicity breaking as the defining feature, with delaying ergodicity explaining related phenomena like the AC Josephson effect, coupled map lattices, and Faraday waves. Theoretical stabilization strategies include localization, prethermalization, dissipation, and error correction in closed and open systems; experimentally, platforms such as trapped ions, solid-state spins, and superconducting qubits demonstrate time crystalline order.
discrete-time-crystalsquantum-physicsergodicity-breakingmany-body-physicsquantum-simulatorstime-translation-symmetry
“Discrete time crystals result from many-body interactions, collective synchronization, and ergodicity breaking”
paper / mikhaillukin / Apr 11
Researchers demonstrate two-qubit entangling gates with 99.5% fidelity on up to 60 neutral atoms in parallel using fast single-pulse optimal control, atomic dark states to minimize scattering, and enhanced Rydberg excitation and cooling. This fidelity surpasses the surface code threshold for quantum error correction. The approach extends to low-error three-qubit gates and supports scalable, reconfigurable architectures for quantum algorithms and simulations.
neutral-atomsquantum-computingentangling-gatesrydberg-interactionsquantum-error-correctionarxiv-paper
“Two-qubit entangling gates achieve 99.5% fidelity on up to 60 atoms in parallel”
paper / mikhaillukin / Mar 13
The framework designs Hamiltonian engineering pulse sequences by systematically incorporating higher-order terms in the Floquet-Magnus expansion, yielding simple decoupling rules that avoid complex non-local commutators. These rules facilitate efficient pulse sequence optimization for dynamical decoupling, quantum sensing, and quantum simulation. An accompanying paper demonstrates applications to quantum sensing in strongly interacting systems.
quantum-physicshamiltonian-engineeringfloquet-magnus-expansiondynamical-decouplingquantum-sensingquantum-simulationpulse-sequence-design
“The framework accounts for higher-order contributions to the Floquet-Magnus expansion in pulse sequence design.”
paper / mikhaillukin / Mar 13
Standard AC dynamical decoupling sequences in strongly interacting quantum systems fail to fully decouple interactions, imposing a fundamental sensitivity limit due to imperfect decoupling. The authors derive higher-order decoupling rules and introduce a sequence building block where the signal period is twice the echo period, surpassing these limits. Experimental validation shows enhanced coherence times and magnetic field sensitivity, advancing quantum sensing and many-body physics applications.
quantum-sensingdynamical-decouplinghamiltonian-engineeringquantum-physicsstrongly-interacting-systemsarXiv-paper
“Standard periodic echo-like AC sensing sequences lead to a fundamental sensitivity limit in strongly interacting systems due to imperfect interaction decoupling.”
paper / mikhaillukin / Mar 13
Fermionic quantum processors using programmable neutral atom arrays encode fermionic models directly into fermionic registers, enabling hardware-efficient simulation via local fermionic gates that preserve Fermi statistics. Non-local tunneling gates are implemented with protocols guaranteeing correct statistics, combined with Rydberg-mediated interactions for efficient digital and variational quantum algorithms like molecular energy estimation. A hybrid fermion-qubit architecture further leverages motional and internal atomic degrees of freedom for quantum phase estimation and lattice gauge theory simulations.
quantum-computingfermionic-systemsneutral-atomsquantum-simulationtweezer-arraysrydberg-gateslattice-gauge-theory
“Fermionic models are locally encoded in a fermionic register using programmable tweezer arrays of fermionic atoms.”
paper / mikhaillukin / Dec 24
Researchers experimentally demonstrate that quantum scrambling near a bistable point generates exponential entanglement, boosting metrological gain. A time-reversal protocol reveals simultaneous exponential growth in metrological gain and out-of-time-order correlators (OTOCs), confirming the theoretical link between scrambling and quantum metrology. The approach yields a 6.8(4) dB improvement over the Standard Quantum Limit (SQL) in a multi-particle system.
quantum-scramblingquantum-metrologyentanglement-generationout-of-time-order-correlatorquantum-informationatomic-physicsarxiv-paper
“Quantum scrambling spreads local information exponentially into many degrees of freedom near a bistable point.”
paper / mikhaillukin / Dec 12
New algorithms enable efficient learning of quantum many-body states using randomized measurements, even without individual particle control or ancilla qubits. They support global fields applied uniformly to all particles and are rigorously proven efficient. Numerical tests validate energy density estimation in U(1) lattice gauge theory and topological order classification under limited measurement access.
quantum-many-bodystate-learninghardware-efficientrandomized-measurementslattice-gauge-theorytopological-ordermachine-learning-quantum
“Modest number of randomized measurements suffices to learn properties of quantum many-body systems”
paper / mikhaillukin / Oct 31
Researchers propose a Floquet engineering approach to simulate non-Abelian spin liquids from Kitaev's honeycomb model using periodic parallel quantum gates. The protocol is implemented in Rydberg atom arrays via coherent qubit transport and controlled-phase gates, enabling preparation, control, and readout of topological states with non-Abelian excitations like Majorana zero modes. Methods for probing fusions, braiding, and extensions to Kitaev materials and lattice gauge theories are outlined, leveraging programmable quantum simulators.
floquet-spin-liquidsrydberg-simulatornon-abelian-topologykitaev-modelquantum-simulationmajorana-modestopological-matter
“A Floquet spin liquid model simulates the non-Abelian spin liquid Hamiltonian in Kitaev's honeycomb model via periodic quantum gate sequences.”
paper / mikhaillukin / Oct 26
QIST represents a critical emerging technology with global investments from over 40 nations, but requires bridging low TRLs in university research to high TRLs for industrial and public use. The proposed Quantum Technology Demonstration Projects (QTDPs) are large-scale public-private partnerships targeting intermediate TRLs to demonstrate clear quantum advantage in user-motivated science breakthroughs. QTDPs enable broad access for diverse scientific communities and promise substantial economic impacts through successful lab-to-practice translation.
quantum-advantagequantum-technologytechnology-roadmapquantum-demonstrationpublic-private-partnershiptrlsqist
“Quantum information science and technology (QIST) is invested in by over 40 nations”
paper / mikhaillukin / Oct 23
Researchers demonstrate Rydberg coherence and two-atom entanglement in arrays at 100-micron distances from nanoscale dielectric devices, overcoming electric field noise challenges. They use coherent qubit manipulation and entanglement-assisted sensing to map and control the spatio-temporal electric field environment. This enables integration of Rydberg arrays with micro/nanoscale photonics and electronics for quantum networking and advanced control.
rydberg-atomsquantum-entanglementatomic-physicsquantum-informationnanoscale-deviceselectric-field-noise
“Rydberg coherence can be generated and maintained at distances of 100 microns from a nanoscale dielectric device.”
paper / mikhaillukin / Sep 26
LED combines error correction with renormalization-group flow to quantify topological states efficiently and robustly, even under incoherent noise. It identifies topological order in simulations of perturbed toric code and provides insights into experimental Rydberg-atom quantum spin liquids. The method extends to generic topological phases, including non-abelian anyons.
topological-ordererror-correctionquantum-computationtoric-coderydberg-atomsquantum-spin-liquid
“LED paradigm allows efficient and robust identification of topological order in the presence of incoherent noise.”
paper / mikhaillukin / Sep 19
Researchers exploit inherent disorder in a 3D dipolar-interacting spin ensemble to probe local thermalization dynamics, observing distinct changes in local correlation decay shapes and timescales when varying engineered exchange anisotropy. These variations stem from intrinsic many-body dynamics and signatures of conservation laws in localized spin clusters, undetectable by global probes. The Floquet-engineered approach enables precise studies of scrambling, thermalization, and hydrodynamics in strongly interacting quantum systems.
quantum-thermalizationfloquet-engineeringdipolar-spinsmany-body-physicslocal-correlationshamiltonian-engineeringquantum-disorder
“Local thermalization can be probed in large-scale many-body systems using inherent disorder.”
paper / mikhaillukin / Sep 8
Rydberg atom arrays, previously limited to unit-disk graphs, now encode arbitrary-connectivity maximum weighted independent set (MWIS), QUBO, and integer factorization via explicit mappings to unit-disk MWIS with at most quadratic qubit overhead. Numerical simulations on small systems show adiabatic timescales for mapped problems correlate strongly with original problem hardness. This extends hardware-efficient quantum optimization to broad combinatorial classes without geometry constraints.
rydberg-atomsquantum-optimizationunit-disk-graphsqubit-encodingcombinatorial-optimizationadiabatic-quantum-computing
“Maximum weighted independent set on graphs with arbitrary connectivity can be encoded into MWIS on unit-disk graphs using Rydberg atom arrays with at most quadratic qubit overhead.”
paper / mikhaillukin / Jul 26
Researchers demonstrate a two-qubit quantum network node using silicon-vacancy (SiV) centers in diamond nanophotonic cavities, with the electron spin as communication qubit and 29Si nuclear spin as memory qubit achieving over two seconds coherence time. Highly strained SiVs suppress electron spin-phonon interactions, enabling electron-photon entangling gates up to 1.5 K and nucleus-photon gates up to 4.3 K. Error detection in nuclear spin-photon gates uses the electron spin as a flag qubit, advancing scalable quantum repeaters.
quantum-networksquantum-memoryerror-detectionsilicon-vacancydiamond-nanophotonicsmulti-qubit-nodequantum-repeaters
“SiV 29Si nuclear spin memory qubit has coherence time exceeding two seconds.”
paper / mikhaillukin / Jul 21
Researchers use a near-surface NV center to probe individual spin dynamics in a 2D dipolar electron spin ensemble on diamond, revealing relaxation rates much slower than expected from nearest-neighbor dipolar strengths. This slowdown correlates with local magnetic field fluctuation timescales and arises from strong dynamical disorder, quantitatively explained by dynamic resonance counting. Resonant spin-lock driving modulates effective local fields, highlighting disorder's role across regimes, enabling microscopic control of quantum thermalization.
quantum-physicsspin-dynamicsnv-centersdipolar-interactionsdynamical-disorderthermalization-dynamicsdisordered-systems
“Relaxation rate of individual spins is significantly slower than expected from independently estimated nearest-neighbor dipolar interactions.”
paper / mikhaillukin / May 7
A unified framework using generic tensor networks computes key solution space properties for broad combinatorial optimization problems, including finding optimal solutions, counting solutions of given size, enumeration, and sampling. Demonstrated on the independent set problem, it applies to computing hardcore lattice gas entropy constants, analyzing overlap gap properties, and evaluating quantum/classical algorithm performance for maximum independent sets. This approach provides a versatile computational tool for statistical mechanics and optimization analysis.
tensor-networkscombinatorial-optimizationindependent-setstatistical-mechanicssolution-spacequantum-algorithms
“Generic tensor networks compute solution space properties including finding one optimum solution, counting solutions of a given size, enumeration, and sampling for a broad class of combinatorial optimization problems.”
paper / mikhaillukin / Apr 7
Quantum simulation for high-energy physics (HEP) has rapidly gained traction in the U.S. particle physics community, marking its first inclusion in decadal planning due to breakthroughs in quantum information sciences and hardware. HEP researchers target intractable problems spanning quantum chromodynamics to cosmology, driving co-design of theory, algorithms, and hardware for quantum advantage. This whitepaper outlines promises, challenges, and decade-scale requirements for realizing these simulations.
quantum-simulationhigh-energy-physicshep-latticequantum-information-sciencequantum-advantagearxiv-paper
“Quantum simulation for HEP is studied for the first time in U.S. decadal particle-physics community planning”
paper / mikhaillukin / Mar 23
Researchers demonstrate quantum logic enhanced sensing using hybrid two-qubit systems from ~10^9 NV centers in diamond, with on-site nitrogen nuclear spins as memory qubits under global control fields. This yields a 30x SNR improvement and over 10x sensitivity gain across protocols like XY8 dynamical decoupling and correlation spectroscopy on synthetic AC fields. The approach is signal-independent and sets a benchmark for quantum-enhanced metrology in solid-state ensembles.
quantum-sensingnv-centerssolid-state-spinsquantum-logicspin-ensemblesdynamical-decouplingquantum-metrology
“Quantum logic enhances SNR by a factor of 30 in macroscopic NV ensemble sensors”
paper / mikhaillukin / Feb 18
Researchers used Rydberg atom arrays with up to 289 qubits to experimentally implement variational quantum algorithms for the Maximum Independent Set problem via hardware-efficient Rydberg blockade encoding. They explored graphs with programmable connectivity, finding problem hardness governed by solution degeneracy and local minima count. On hardest instances, the quantum approach achieved superlinear speedup over classical simulated annealing in finding exact solutions within deep circuit regimes.
quantum-optimizationmaximum-independent-setrydberg-atomsquantum-algorithmsquantum-speedupvariational-algorithmsneutral-atom-arrays
“Rydberg atom arrays with up to 289 qubits were used in 2D for quantum algorithms”
paper / mikhaillukin / Jan 11
Theoretical analysis of Rydberg atom array experiments reveals that a quasi-adiabatic protocol can prepare the resonating valence bond (RVB) fixed point of the topological spin liquid phase in time linear in system size. A two-parameter variational tensor network manifold accurately captures the many-body dynamics, confirming emergence of topological order in non-equilibrium states. This optimizes preparation beyond the original experimental approach, targeting hard dimer configurations.
quantum-spin-liquidsrydberg-atomstopological-ordertensor-networksquantum-simulationstate-preparation
“Quasi-adiabatic state preparation in Rydberg atom arrays can target the RVB state of hard dimers in time scaling linearly with atom number”
paper / mikhaillukin / Jan 8
Researchers demonstrate a deterministic source of arbitrarily temporally shaped single-photon pulses using a silicon-vacancy center in a fiber-integrated diamond nanophotonic cavity. The system achieves 14.9% detection efficiency and g^(2)(0) = 0.0168 purity, with streams of up to 11 consecutively detected single photons. This platform supports on-demand generation of correlated photon streams like cluster states via spin-photon entangling gates, advancing quantum networks and information processing.
single-photon-sourcediamond-nanophotonicssilicon-vacancy-centerquantum-opticsquantum-informationfiber-integrationphoton-entanglement
“Detection efficiency of 14.9% for shaped single-photon pulses”
paper / mikhaillukin / Dec 28
Quantum networks provide information-theoretic security for distributed voting, overcoming classical computational complexity limits vulnerable to quantum attacks. Ballot information encoded in quantum states achieves exponential reduction in communication complexity versus classical methods. The protocol features efficient anonymous queuing and requires quantum memories scaling only logarithmically with voter numbers, enhancing noise-robustness for realistic implementations.
quantum-votinginformation-theoretic-securityquantum-networksquantum-cryptographyelection-securityquantum-memoriesarxiv-paper
“Quantum networks enable information-theoretic security for distributed voting schemes”
paper / mikhaillukin / Dec 20
Theoretical study of square lattice Rydberg atom arrays reveals bulk first-order and continuous quantum phase transitions, analyzed via quantum Monte Carlo and Landau-Ginzburg-Wilson theory. Under open boundary conditions, boundaries exhibit a distinct second-order quantum phase transition decoupled from the bulk. These findings elucidate experimental observations and guide adiabatic preparation of quantum phases and optimization on Rydberg platforms.
quantum-phase-transitionsrydberg-atomsquantum-simulatorsmonte-carlo-simulationslandau-ginzburg-theoryboundary-conditionsarxiv-paper
“Square Rydberg atom arrays on a square lattice exhibit both first-order and continuous quantum phase transitions in the bulk.”
paper / mikhaillukin / Dec 20
Hybrid-CCNN combines unsupervised dimensionality reduction and clustering with supervised interpretable CCNNs to analyze snapshots from Rydberg atom array quantum simulators on square lattices. It identifies five distinct quantum phase regions, refines boundaries, and extracts phase-specific correlations revealing quantum fluctuations in the striated phase plus two previously undetected rhombic and boundary-ordered phases. This approach demonstrates ML's power for automated discovery of correlated quantum matter structures missed by manual analysis.
machine-learningquantum-phasesquantum-simulatorrydberg-atomsccnnquantum-physicsarxiv-paper
“Hybrid-CCNN identifies five distinct quantum phase regions in Rydberg simulator data”
paper / mikhaillukin / Dec 7
Researchers demonstrate a quantum processor using optical tweezers to trap and transport neutral atom arrays, enabling coherent, parallel qubit shuttling across 2D for dynamic nonlocal connectivity. The architecture generates programmable entangled graph states including 7-qubit Steane codes, 19-qubit surface codes, and 24-qubit toric codes via Rydberg-mediated entanglement. It supports hybrid analog-digital quantum simulations, observing non-monotonic entanglement dynamics from many-body scars.
quantum-processorneutral-atomsrydberg-statesentangled-statesquantum-error-correctionquantum-simulationarxiv-paper
“Entangled qubits are coherently transported in parallel across two spatial dimensions between single- and two-qubit operation layers.”
paper / mikhaillukin / Dec 3
Linear Cross-Entropy Benchmark (XEB) inadequately certifies quantum advantage in random circuit sampling, as it approximates fidelity only under specific benign conditions with honest noisy quantum circuits. In adversarial settings, efficient classical algorithms achieve high XEB scores—2-12% of experimental values—using 1 GPU in 2 seconds by exploiting XEB vulnerabilities, without full quantum simulation. These classical methods scale better than noisy quantum devices for common ensembles, revealing XEB's limitations as a fidelity proxy unless stringent conditions are verified.
quantum-advantagecross-entropy-benchmarkquantum-circuitsfidelityclassical-simulationquantum-computing
“An efficient classical algorithm achieves XEB values 2-12% of those from quantum experiments using 1 GPU in 2 seconds”
paper / mikhaillukin / Nov 8
Researchers demonstrate a few-pixel beam steering device using electrostatic gating of excitons in a MoSe2 monolayer, leveraging its high reflectivity and strong light-matter interactions with a graphene split-gate geometry. This enables continuous 10° beam deflection, 2D steering, and switching times as fast as 1.6 ns. The platform supports atomically thin optical systems like switchable beam arrays and quantum metasurfaces at the fundamental thickness limit.
beam-steeringnanosecond-switchingatomically-thin-reflectormo-se2-excitonsgraphene-gatesoptical-metasurfaces2d-materials-optics
“The device achieves continuously tunable beam deflection over a 10° range.”
paper / mikhaillukin / Oct 27
Researchers introduce phase modulation of lasers reflected off chirped Bragg gratings (CBGs) to generate amplitude modulation for two-photon Raman driving of hyperfine qubits, replacing traditional methods. This passive, efficient technique supports high-power lasers, yielding 2 MHz Rabi frequencies with photon-scattering error rates below 2e-4 per π-pulse across ~300 neutral 87Rb qubits in optical tweezers. It ensures improved quantum coherence and integrates with local addressing for scalable single-qubit operations in atomic and ion systems.
quantum-computinghyperfine-qubitsraman-drivingchirped-bragg-gratingneutral-atomsoptical-tweezersqubit-control
“CBG-based phase modulation achieves 2 MHz Rabi frequencies when globally driving ~300 neutral 87Rb qubits in optical tweezers.”