Abstract：
:The wavefunction is the complex distribution used to completely describe a quantum system, and is central to quantum theory. But despite its fundamental role, it is typically introduced as an abstract element of the theory with no explicit definition. Rather, physicists come to a working understanding of the wavefunction through its use to calculate measurement outcome probabilities by way of the Born rule. At present, the wavefunction is determined through tomographic methods, which estimate the wavefunction most consistent with a diverse collection of measurements. The indirectness of these methods compounds the problem of defining the wavefunction. Here we show that the wavefunction can be measured directly by the sequential measurement of two complementary variables of the system. The crux of our method is that the first measurement is performed in a gentle way through weak measurement, so as not to invalidate the second. The result is that the real and imaginary components of the wavefunction appear directly on our measurement apparatus. We give an experimental example by directly measuring the transverse spatial wavefunction of a single photon, a task not previously realized by any method. We show that the concept is universal, being applicable to other degrees of freedom of the photon, such as polarization or frequency, and to other quantum systems--for example, electron spins, SQUIDs (superconducting quantum interference devices) and trapped ions. Consequently, this method gives the wavefunction a straightforward and general definition in terms of a specific set of experimental operations. We expect it to expand the range of quantum systems that can be characterized and to initiate new avenues in fundamental quantum theory.
journal_name
Naturejournal_title
Natureauthors
Lundeen JS,Sutherland B,Patel A,Stewart C,Bamber Cdoi
10.1038/nature10120subject
Has Abstractpub_date
2011-06-08 00:00:00pages
188-91issue
7350eissn
0028-0836issn
1476-4687pii
nature10120journal_volume
474pub_type
杂志文章相关文献
NATURE文献大全abstract：:Vaccines rarely provide full protection from disease. Nevertheless, partially effective (imperfect) vaccines may be used to protect both individuals and whole populations. We studied the potential impact of different types of imperfect vaccines on the evolution of pathogen virulence (induced host mortality) and the co...
journal_title：Nature
pub_type： 杂志文章
doi：10.1038/414751a
更新日期：2001-12-13 00:00:00
abstract：:Fluctuations in the counting rate of photons originating from uncorrelated point sources become, within the coherently illuminated area, slightly enhanced compared to a random sequence of classical particles. This phenomenon, known in astronomy as the Hanbury Brown-Twiss effect, is a consequence of quantum interferenc...
journal_title：Nature
pub_type： 杂志文章
doi：10.1038/nature00911
更新日期：2002-07-25 00:00:00
abstract：:First-order difference equations arise in many contexts in the biological, economic and social sciences. Such equations, even though simple and deterministic, can exhibit a surprising array of dynamical behaviour, from stable points, to a bifurcating hiearchy of stable cycles, to apparently random fluctuations. There ...
journal_title：Nature
pub_type： 杂志文章
doi：10.1038/261459a0
更新日期：1976-06-10 00:00:00
abstract：:The satellites Rhea and Dione orbit within the magnetosphere of Saturn, where they are exposed to particle irradiation from trapped ions. A similar situation applies to the galilean moons Europa, Ganymede and Callisto, which reside within Jupiter's radiation belts. All of these satellites have surfaces rich in water i...
journal_title：Nature
pub_type： 杂志文章
doi：10.1038/40348
更新日期：1997-07-03 00:00:00
abstract：:The Ca2+ + Mg2+-activated ATPase of the sarcoplasmic reticulum is responsible for the active Ca2+ transport of this membrane system, the key feature of which is the formation of an energy-rich phosphorylated transport enzyme (EP) and its conversion. To understand the Ca2+-transport mechanism, it is essential to clarif...
journal_title：Nature
pub_type： 杂志文章
doi：10.1038/290271a0
更新日期：1981-03-19 00:00:00
abstract：:Environmental change is rapidly accelerating, and many species will need to adapt to survive1. Ensuring that protected areas cover populations across a broad range of environmental conditions could safeguard the processes that lead to such adaptations1-3. However, international conservation policies have largely negle...
journal_title：Nature
pub_type： 杂志文章
doi：10.1038/s41586-020-2138-7
更新日期：2020-04-01 00:00:00
abstract：:Protein-tyrosine phosphatases (PTPs) are vital for regulating tryosine phosphorylation in many processes, including growth and differentiation. The regulation of receptor-like PTP (RPTP) activity remains poorly understood, but based on the crystal structure of RPTPalpha domain 1 we have proposed that dimerization can ...
journal_title：Nature
pub_type： 杂志文章
doi：10.1038/44170
更新日期：1999-10-07 00:00:00
abstract：:The Ras proto-oncogene is a central component of mitogenic signal-transduction pathways, and is essential for cells both to leave a quiescent state (G0) and to pass through the G1/S transition of the cell cycle. The mechanism by which Ras signalling regulates cell-cycle progression is unclear, however. Here we report ...
journal_title：Nature
pub_type： 杂志文章
doi：10.1038/386177a0
更新日期：1997-03-13 00:00:00
abstract：:Symbolic arithmetic is fundamental to science, technology and economics, but its acquisition by children typically requires years of effort, instruction and drill. When adults perform mental arithmetic, they activate nonsymbolic, approximate number representations, and their performance suffers if this nonsymbolic sys...
journal_title：Nature
pub_type： 杂志文章
doi：10.1038/nature05850
更新日期：2007-05-31 00:00:00
abstract：:Two approaches to the antibody-directed targeting of toxic or cytolytic activity and augmentation of cellular immune responses have been explored for tumour immunotherapy, but so far success has been limited. Obstacles facing immunotherapy are the limited accessibility of antibodies or antibody conjugates to solid tum...
journal_title：Nature
pub_type： 杂志文章
doi：10.1038/385078a0
更新日期：1997-01-02 00:00:00
abstract：:In 1928, Dirac published an equation 1 that combined quantum mechanics and special relativity. Negative-energy solutions to this equation, rather than being unphysical as initially thought, represented a class of hitherto unobserved and unimagined particles-antimatter. The existence of particles of antimatter was conf...
journal_title：Nature
pub_type： 杂志文章
doi：10.1038/s41586-018-0017-2
更新日期：2018-05-01 00:00:00
abstract：:Small synthetic molecules called growth-hormone secretagogues (GHSs) stimulate the release of growth hormone (GH) from the pituitary. They act through GHS-R, a G-protein-coupled receptor for which the ligand is unknown. Recent cloning of GHS-R strongly suggests that an endogenous ligand for the receptor does exist and...
journal_title：Nature
pub_type： 杂志文章
doi：10.1038/45230
更新日期：1999-12-09 00:00:00
abstract：:When present in single-stranded DNA, palindromic or quasi-palindromic sequences have the potential to form complex secondary structures, including hairpins, which may facilitate interstrand misalignment of direct repeats and be responsible for diverse types of replication-based mutations, including deletions, addition...
journal_title：Nature
pub_type： 杂志文章
doi：10.1038/352544a0
更新日期：1991-08-08 00:00:00
abstract：:The brain cholecystokinin-B/gastrin receptor (CCK-B/gastrin) has been implicated in mediating anxiety, panic attacks, satiety, and the perception of pain. The canine and human CCK-B/gastrin receptors share 90% amino-acid identity and have similar agonist affinities. These receptors can be selectively blocked by the no...
journal_title：Nature
pub_type： 杂志文章
doi：10.1038/362348a0
更新日期：1993-03-25 00:00:00
abstract：:The sequencing of ancient DNA has enabled the reconstruction of speciation, migration and admixture events for extinct taxa1. However, the irreversible post-mortem degradation2 of ancient DNA has so far limited its recovery-outside permafrost areas-to specimens that are not older than approximately 0.5 million years (...
journal_title：Nature
pub_type： 历史文章,杂志文章
doi：10.1038/s41586-019-1555-y
更新日期：2019-10-01 00:00:00
abstract：:Biochemical and structural studies have shown that the initiation of RNA polymerase II transcription proceeds in the following stages: assembly of the polymerase with general transcription factors and promoter DNA in a 'closed' preinitiation complex (PIC); unwinding of about 15 base pairs of the promoter DNA to form a...
journal_title：Nature
pub_type： 杂志文章
doi：10.1038/nature14882
更新日期：2015-09-10 00:00:00
abstract：:Excitatory synaptic transmission in the central nervous system is mediated primarily by the release of glutamate from presynaptic terminals onto postsynaptic channels gated by N-methyl-D-aspartate (NMDA) and alpha-amino-3-hydroxy-5-methylisoxazole-4-propionate (AMPA) receptors. The myriad intracellular responses arisi...
journal_title：Nature
pub_type： 杂志文章
doi：10.1038/39062
更新日期：1997-10-02 00:00:00
abstract：:CRISPR-Cas genome-editing nucleases hold substantial promise for developing human therapeutic applications1-6 but identifying unwanted off-target mutations is important for clinical translation7. A well-validated method that can reliably identify off-targets in vivo has not been described to date, which means it is cu...
journal_title：Nature
pub_type： 杂志文章
doi：10.1038/s41586-018-0500-9
更新日期：2018-09-01 00:00:00
abstract：:RNA is involved in many biological functions, ranging from information storage and transfer to the catalysis of reactions involving both nucleic acids and proteins. Previous crystallographic studies on RNA oligomeric chains provide only averaged structures or information limited in resolution. The oligomer [U(U-A)6A]2...
journal_title：Nature
pub_type： 杂志文章
doi：10.1038/335375a0
更新日期：1988-09-22 00:00:00
abstract：:IgE and its receptors are believed to have evolved as a mechanism to protect mammals against parasites. But other and intrinsically innocuous antigens can subvert this system to provoke an allergic response. For human populations in industrialized countries, allergy and asthma now represent a far greater threat than p...
journal_title：Nature
pub_type： 杂志文章,评审
doi：10.1038/366421a0
更新日期：1993-12-02 00:00:00
abstract：:The development of a eutherian mammal as a male is a consequence of testis formation in the embryo, which is thought to be initiated by a gene on the Y chromosome. In the absence of this gene, ovaries are formed and female characteristics develop. Sex determination therefore hinges on the action of this testis-determi...
journal_title：Nature
pub_type： 杂志文章
doi：10.1038/348450a0
更新日期：1990-11-29 00:00:00
abstract：:Although the influence of electrical activity on neural development has been studied extensively, experiments have only recently focused on the role of activity in the development of the mammalian central nervous system (CNS). Using tetrodotoxin (TTX) to abolish sodium-mediated action potentials, studies on the visual...
journal_title：Nature
pub_type： 杂志文章
doi：10.1038/323156a0
更新日期：1986-09-11 00:00:00
abstract：:Compared with atoms, molecules have a rich internal structure that offers many opportunities for technological and scientific advancement. The study of this structure could yield critical insights into quantum chemistry, new methods for manipulating quantum information, and improved tests of discrete symmetry violatio...
journal_title：Nature
pub_type： 杂志文章
doi：10.1038/nature11937
更新日期：2013-03-28 00:00:00
abstract：:The holotype of Deinocheirus mirificus was collected by the 1965 Polish-Mongolian Palaeontological Expedition at Altan Uul III in the southern Gobi of Mongolia. Because the holotype consists mostly of giant forelimbs (2.4 m in length) with scapulocoracoids, for almost 50 years Deinocheirus has remained one of the most...
journal_title：Nature
pub_type： 杂志文章
doi：10.1038/nature13874
更新日期：2014-11-13 00:00:00
abstract：:The distribution, accumulation and circulation of oxygen and hydrogen in Earth's interior dictate the geochemical evolution of the hydrosphere, atmosphere and biosphere. The oxygen-rich atmosphere and iron-rich core represent two end-members of the oxygen-iron (O-Fe) system, overlapping with the entire pressure-temper...
journal_title：Nature
pub_type： 历史文章,杂志文章
doi：10.1038/nature18018
更新日期：2016-06-09 00:00:00
abstract：:Nitrogen (N) limits the productivity of many ecosystems worldwide, thereby restricting the ability of terrestrial ecosystems to offset the effects of rising atmospheric CO(2) emissions naturally. Understanding input pathways of bioavailable N is therefore paramount for predicting carbon (C) storage on land, particular...
journal_title：Nature
pub_type： 杂志文章
doi：10.1038/nature10415
更新日期：2011-08-31 00:00:00
abstract：:Combined analyses of gene networks and DNA sequence variation can provide new insights into the aetiology of common diseases that may not be apparent from genome-wide association studies alone. Recent advances in rat genomics are facilitating systems-genetics approaches. Here we report the use of integrated genome-wid...
journal_title：Nature
pub_type： 杂志文章
doi：10.1038/nature09386
更新日期：2010-09-23 00:00:00
abstract：:An amendment to this paper has been published and can be accessed via a link at the top of the paper. ...
journal_title：Nature
pub_type： 已发布勘误
doi：10.1038/s41586-020-2789-4
更新日期：2020-10-01 00:00:00
abstract：:The plasma membrane-bound mammalian ras proteins of relative molecular mass 21,000 (ras p21) share biochemical and structural properties with other guanine nucleotide-binding regulatory proteins (G-proteins). Oncogenic ras p21 variants result from amino acid substitutions at specific positions that cause p21 to occur ...
journal_title：Nature
pub_type： 杂志文章
doi：10.1038/335090a0
更新日期：1988-09-01 00:00:00
abstract：:Interactions between animal viruses and antiviral antisera may exceptionally result in an apparent increase in viral infectivity. Halstead and coworkers demonstrated enhanced replication of dengue virus (a Flavivirus, family Togaviridae) in human or simian peripheral blood leucocytes carrying Fc receptors at subneutra...
journal_title：Nature
pub_type： 杂志文章
doi：10.1038/282509a0
更新日期：1979-11-29 00:00:00
