Search

Funding: This work is supported by Westlake University (Project No. 041020100118) and Program 2018R01002 supported by Leading Innovative and Entrepreneur Team Introduction Program of Zhejiang. PS acknowledges bilateral Greece-Russia Polisimulator project co-financed by Greece and the EU Regional Development Fund. HO acknowledges Grant No. EPSRC EP/S014403/1. The authors acknowledge Russian Science Foundation Grant No. 19-72-20120 for financial support. Numerical simulations have been supported by the Grant of the President of the Russian Federation for state support of young Russian scientists (Grant No. MK-4729.2021.1.2). We resolve single-shot polariton condensate polarization dynamics, revealing a high degree of circular polarization persistent up to T = 170 K. The statistical analysis of pulse-to-pulse polariton condensate polarization elucidates the stochastic nature of the polarization pinning process, which is strongly dependent on the pump laser intensity and polarization. Our experiments show that by spatial trapping and isolating condensates from their noisy environment it is possible to form strongly spin-polarized polariton condensates at high temperatures, offering a promising route to the realization of polariton spin lattices for quantum simulations. Publisher PDF

Additional file 5 Additional Table 5. The list of queries that were used to communicate with the Ensembl data repositories.

Additional file 2 Additional Table 2. The number of events/co-occurrences of homologous and non-homologous TISs (in human as reference) with the two groups of human-specific and non-specific TRs and their p-values, calculated by Fisher’s exact test in each method across TR categories 1, 2, 3 and 4.

The stability of spin of macroscopic quantum states to intrinsic noise is studied for non-resonantly pumped optically-trapped polariton condensates. We demonstrate flipping between the two spinpolarised states with >10⁴ slow-down of the flip rate by tuning the optical pump power. Individual spin flips faster than 50 picosecond are time resolved using single-shot streak camera imaging. We reproduce our results within a mean-field model accounting for cross-spin scattering between excitons and polaritons, yielding a ratio of cross- to co-spin scattering of ~0.6, in contrast with previous literature suggestions., ERC LINASS 320503. Leverhulme Trust Grant No. VP1-2013-011. Bilateral Greece-Russia “Polisimulator” project co-financed by Greece and the EU Regional Development Fund. Stavros Niarchos Foundation, “ARCHERS” project. Horizon 2020 programme (No. FETPROACT-2016 732894-HOT). CONACYT (Mexico) grant No. 251808. Institute for Basic Science in Korea (IBS-R024-D1)

supplemental document

Optical cooling methods are generally applicable to a very restricted range of species. As a means of overcoming this problem, we explore the effect of the retarded interaction of any polarisable particle (an atom, a molecule or even a micromirror) with itself, similarly to cavity-mediated cooling. We use the transfer matrix method, extended to allow us to handle moving scatterers, to explore the most general configuration of a mobile particle interacting with any 1D combination of fixed optical elements. Remarkably, this model allows a solution in closed form for the force acting on the particle, without any a priori restriction on the nature of the particle., peer-reviewed

We have calculated, using a classical approach, the frictional force on a polarisable particle which is illuminated with far-detuned light and coupled, via the dipole force, to its reflection. Established methods for cooling atoms with light require a closed optical transition; they rely on the atom to provide the necessary dissipation. A new breed of techniques is emerging in which particles and light are coupled using the dipole rather than the scattering force; for these, it is the light, not the particle, which provides dissipation. Examples include cavity-mediated cooling and the proposed mirror-mediated cooling. For these techniques, the only property required of the particle is that it be polarisable; specifically, there is no need for a closed optical transition. Potentially, we can achieve direct, optical cooling of molecules and even much larger structures, such as micro-cantilevers., N/A

Cooling and trapping of atoms with light provides us with samples far colder and denser than possible by any other means and enables us to study and control these systems in exquisite detail [1]. We can not only learn about these systems, but can devise experiments of such precision that we test the underlying physics. It is unfortunate therefore that the most effective techniques, Doppler cooling and the Magneto Optical Trap, rely on a simple energy level structure found only in a handful of elements. Finally, I will present an approach in which a particle can be cooled using the dipole, rather than the scattering, force. The dipole force is conservative, but by allowing the potential to vary in time, one can change the energy of a trapped particle. Specifically, if the potential depends on the position of the particle with some time delay, we can create a friction-like force [5, 6], and we are currently building an experiment to demonstrate this effect. This technique is not restricted to atoms with a simple structure, but requires only that the particle be polarisable; in principle, therefore, it can be extended without significant change to direct optical cooling of molecules.

This research was supported by UK Engineering and Physical Sciences Research Council grants EP/G060649/1 and EP/L027151/1 , and ERC grant LINASS 320503 . F.B. thanks the supports from the Winton Programme for the Physics of Sustainability. Publisher PDF

We demonstrate that multiply coupled spinor polariton condensates can be optically tuned through a sequence of spin-ordered phases by changing the coupling strength between nearest neighbors. For closed four-condensate chains these phases span from ferromagnetic (FM) to antiferromagnetic (AFM), separated by an unexpected crossover phase. This crossover phase is composed of alternating FM-AFM bonds. For larger eight-condensate chains, we show the critical role of spatial inhomogeneities and demonstrate a scheme to overcome them and prepare any desired spin state. Our observations thus demonstrate a fully controllable nonequilibrium spin lattice., We acknowledge Grants No. EPSRC EP/L027151/1, No. EU INDEX 289968, No. ERC “POLAFLOW” Starting Grant, ERC LINASS 320503, Spanish MEC (MAT2008- 01555), Mexican CONACYT 251808, Leverhulme Trust Grant No. VP1-2013-011 and Fundación La Caixa. H. S. and I. S. acknowledge support by the Research Fund of the University of Iceland, The Icelandic Research Fund, Grant No. 163082-051. T. L. was supported by the MOE AcRF Tier 1 Grant No. 2016-T1-001-084. P. S. acknowledges financial support from the Stavros Niarchos Foundation, “ARCHERS” project.

We report spin and intensity coupling of an exciton-polariton condensate to the mechanical vibrations of a circular membrane microcavity. We optically drive the microcavity resonator at the lowest mechanical resonance frequency while creating an optically-trapped spin-polarized polariton condensate in different locations on the microcavity, and observe spin and intensity oscillations of the condensate at the vibration frequency of the resonator. Spin oscillations are induced by vibrational strain driving, whilst the modulation of the optical trap due to the displacement of the membrane causes intensity oscillations in the condensate emission. Our results demonstrate spin-phonon coupling in a macroscopically coherent condensate., 5 pages

Trapping light with noble metal nanostructures overcomes the diffraction limit and can confine light to volumes typically on the order of 30 cubic nanometers. We found that individual atomic features inside the gap of a plasmonic nanoassembly can localize light to volumes well below 1 cubic nanometer (“picocavities”), enabling optical experiments on the atomic scale. These atomic features are dynamically formed and disassembled by laser irradiation. Although unstable at room temperature, picocavities can be stabilized at cryogenic temperatures, allowing single atomic cavities to be probed for many minutes. Unlike traditional optomechanical resonators, such extreme optical confinement yields a factor of 106 enhancement of optomechanical coupling between the picocavity field and vibrations of individual molecular bonds. This work sets the basis for developing nanoscale nonlinear quantum optics on the single-molecule level., We acknowledge financial support from EPSRC grants EP/G060649/1 and EP/L027151/1, and ERC grant LINASS 320503. MKS, YZ, AD, RE, and JA acknowledge financial support from Project FIS2013- 41184-P from MINECO and IT756-13 from the Basque Government consolidated groups. FB acknowledges support from the Winton Programme for the Physics of Sustainability. RC acknowledges support from the Dr. Manmohan Singh scholarship from St. John’s College. CC thanks NPL for support. RE acknowledges support from the Fellows Gipuzkoa Program of the Gipuzkoako Foru Aldundia via FEDER funds of the European Union “Una manera de hacer Europa”.

P. G. L. and A. V. K. acknowledge EPSRC through Programme Grant on Hybrid Polaritonics EP/M025330/1 and EP/F026455/1 for co-supporting this work. N. G. B acknowledges financial support by the Ministry of Education and Science of the Russian Federation 1425320 (Project DOI: RFMEFI58114X0006). Y. G. R. acknowledges financial support by CONACYT (Mexico) under Grant No. 251808. We investigate the phase coupling between spatially separated polariton condensates under nonresonant optical pulsed excitation. In the simple case of two condensates, we observe phase locking either in symmetric or antisymmetric states. We demonstrate that the coupling symmetry depends both on the separation distance and outflow velocity from the condensates. We interpret the observations through stimulated relaxation of polaritons to the phase configuration with the highest occupation. We derive an analytic criterion for the phase locking of a pair-polariton condensate and extend it to polariton multiplets. In the case of three condensates, we predict theoretically and observe experimentally either in-phase locking or the appearance of phase winding with phase differences of ±2π/3 between neighbors. The latter state corresponds to a vortex of winding number ±1 across the three polariton condensates. Publisher PDF

The authors thank Javier Aizpurua (CSIC − UPV/EHU/DIPC) for helpful discussions. We acknowledge financial support from EPSRC Grants EP/G060649/1, EP/K028510/1, EP/L027151/1, ERC Grant LINASS 320503. F.B. acknowledges support from the Winton Programme for the Physics of Sustainability. R.C. acknowledges support from the Dr. Manmohan Singh scholarship from St. John’s College. Coupling noble metal nanoparticles by a 1 nm gap to an underlying gold mirror confines light to extremely small volumes, useful for sensing on the nanoscale. Individually measuring 10 000 of such gold nanoparticles of increasing size dramatically shows the different scaling of their optical scattering (far-field) and surface-enhanced Raman emission (SERS, near-field). Linear red-shifts of the coupled plasmon modes are seen with increasing size, matching theory. The total SERS from the few hundred molecules under each nanoparticle dramatically increases with increasing size. This scaling shows that maximum SERS emission is always produced from the largest nanoparticles, irrespective of tuning to any plasmonic resonances. Changes of particle facet with nanoparticle size result in vastly weaker scaling of the near-field SERS, without much modifying the far-field, and allows simple approaches for optimizing practical sensing. Publisher PDF

Nanoactuators are a key component for developing nanomachinery. Here, an electrically driven device yielding actuation stresses exceeding 1 MPa withintegrated optical readout is demonstrated. 10 nm thick Al2 O3 electrolyte films are sandwiched between graphene and Au electrodes. These allow reversible room-temperature solid-state redox reactions, producing Al metal and O2 gas in a memristive-type switching device. The resulting high-pressure oxygen micro-fuel reservoirs are encapsulated under the graphene, swelling to heights of up to 1 µm, which can be dynamically tracked by plasmonic rulers. Unlike standard memristors where the memristive redox reaction occurs in single or few conductive filaments, the mechanical deformation forces the creation of new filaments over the whole area of the inflated film. The resulting on-off resistance ratios reach 108 in some cycles. The synchronization of nanoactuation and memristive switching in these devices is compatible with large-scale fabrication and has potential for precise and electrically monitored actuation technology.

Tunable spin correlations are found to arise between two neighboring trapped exciton-polariton condensates which spin-polarize spontaneously. We observe a crossover from an antiferromagnetic- to a ferromagnetic pair state by reducing the coupling barrier in real-time using control of the imprinted pattern of pump light. Fast optical switching of both condensates is then achieved by resonantly but weakly triggering only a single condensate. These effects can be explained as the competition between spin bifurcations and spin-preserving Josephson coupling between the two condensates, and open the way to polariton Bose-Hubbard ladders., Comment: 5 pages, 4 figures