Supersensitivity Phase Research Articles

Supersensitive phase estimation by thermal light in a Kerr-nonlinear interferometric setup

Supersensitive phase estimation by thermal light in a Kerr-nonlinear interferometric setup

Double-port homodyne detection in a squeezed-state interferometry with a binary-outcome data processing

Performing homodyne detection at a single output port of a squeezed-state light interferometer and then separating the measurement quadrature into two intervals can realize super-resolving and super-sensitive phase measurements, which is equivalent to a binary-outcome measurement. Obviously, the single-port homodyne detection may lose almost part of the phase information, reducing the estimation precision. Here, we propose a data-processing technique over the double-port homodyne detection, where the two-dimensional measurement quadrature (p 1, p 2) has been divided into two regions. With such a binary-outcome measurement, we estimate the phase shift accumulated in the interferometer by inverting the output signal. By analyzing the full width at half maximum of the signal and the phase sensitivity, we show that both the resolution and the achievable sensitivity are better than that of the previous binary-outcome scheme.

A quantum-enhanced wide-field phase imager.

Quantum techniques can be used to enhance the signal-to-noise ratio in optical imaging. Leveraging the latest advances in single-photon avalanche diode array cameras and multiphoton detection techniques, here, we introduce a supersensitive phase imager, which uses space-polarization hyperentanglement to operate over a large field of view without the need of scanning operation. We show quantum-enhanced imaging of birefringent and nonbirefringent phase samples over large areas, with sensitivity improvements over equivalent classical measurements carried out with equal number of photons. The potential applicability is demonstrated by imaging a biomedical protein microarray sample. Our technology is inherently scalable to high-resolution images and represents an essential step toward practical quantum-enhanced imaging.

Single-Port Homodyne Detection in a Squeezed-State Interferometry with Optimal Data Processing

Performing homodyne detection at a single output port of a squeezed-state light interferometer and then separating the measurement quadrature into several bins can realize superresolving and supersensitive phase measurements. However, the phase resolution and the achievable phase sensitivity depend on the bin size that is adopted in the data processing. By maximizing classical Fisher information, we analytically derive an optimal value of the bin size and the associated best sensitivity for the case of three bins, which can be regarded as a three-outcome measurement. Our results indicate that both the resolution and the achievable sensitivity are better than that of the previous binary–outcome case. Finally, we present an approximate maximum Likelihood estimator to asymptotically saturate the ultimate lower bound of the phase sensitivity.

Versatile Super-Sensitive Metrology Using Induced Coherence

We theoretically analyze the phase sensitivity of the Induced-Coherence (Mandel-Type) Interferometer, including the case where the sensitivity is "boosted" into the bright input regime with coherent-light seeding. We find scaling which reaches below the shot noise limit, even when seeding the spatial mode which does not interact with the sample – or when seeding the undetected mode. It is a hybrid of a linear and a non-linear (Yurke-Type) interferometer, and aside from the supersensitivity, is distinguished from other systems by "preferring" an imbalance in the gains of the two non-linearities (with the second gain being optimal at low values), and non-monotonic behavior of the sensitivity as a function of the gain of the second non-linearity. Furthermore, the setup allows use of subtracted intensity measurements, instead of direct (additive) or homodyne measurements – a significant practical advantage. Bright, super-sensitive phase estimation of an object with different light fields for interaction and detection is possible, with various potential applications, especially in cases where the sample may be sensitive to light, or is most interesting in frequency domains outside what is easily detected, or when desiring bright-light phase estimation with sensitive/delicate detectors. We use an analysis in terms of general squeezing and discover that super-sensitivity occurs only in this case – that is, the effect is not present with the spontaneous-parametric-down-conversion approximation, which many previous analyses and experiments have focused on.

Data processing over single-port homodyne detection to realize superresolution and supersensitivity

Performing homodyne detection at one port of squeezed-state light interferometer and then binarzing measurement data are important to achieve super-resolving and super-sensitive phase measurements. Here we propose a new data-processing technique by dividing the measurement quadrature into three bins (equivalent to a multi-outcome measurement), which leads to a higher improvement in the phase resolution and the phase sensitivity under realistic experimental condition. Furthermore, we develop a new phase-estimation protocol based on a combination of the inversion estimators of each outcome and show that the estimator can saturate the Cramer-Rao lower bound, similar to asymptotically unbiased maximum likelihood estimator.

Super-sensitive phase estimation with coherent boosted light using parity measurements**Project supported by the National Natural Science Foundation of China (Grant No. 11665010), the Key Laboratory of Low-Dimensional Quantum Structures and Quantum Control of Ministry of Education, China (Grant No. QSQC1414), and the Scientific Research Fund of Hunan Provincial Education Department, China (Grant No. 17B055).

We consider a passive and active hybrid interferometer for phase estimation, which can reach the sub-shot-noise limit in phase sensitivity with only the cheapest coherent sources. This scheme is formed by adding an optical parametric amplifier before a Mach–Zehnder interferometer. It is shown that our hybrid protocol can obtain a better quantum Cramer–Rao bound than the pure active (e.g., SU(1,1)) interferometer, and this precision can be reached by implementing the parity measurements. Furthermore, we also draw a detailed comparison between our scheme and the scheme suggested by Caves [Phys. Rev. D 23 1693 (1981)], and it is found that the optimal phase sensitivity gain obtained in our scheme is always larger than that in Caves’ scheme.

Improving the phase super-sensitivity of squeezing-assisted interferometers by squeeze factor unbalancing

The sensitivity properties of an SU(1,1) interferometer made of two cascaded parametric amplifiers, as well as of an ordinary SU(2) interferometer preceded by a squeezer and followed by an anti-squeezer, are theoretically investigated. Several possible experimental configurations are considered, such as the absence or presence of a seed beam, direct or homodyne detection scheme. In all cases we formulate the optimal conditions to achieve phase super-sensitivity, meaning a sensitivity overcoming the shot-noise limit. We show that for a given gain of the first parametric amplifier, unbalancing the interferometer by increasing the gain of the second amplifier improves the interferometer properties. In particular, a broader super-sensitivity phase range and a better overall sensitivity can be achieved by gain unbalancing.

Depression treatment by withdrawal of short-term low-dose antipsychotic, a proof-of-concept randomized double-blind study

Background and objectiveBecause increased dopamine neurotransmission occurs with most antidepressants, and because antipsychotics cause behavioural supersensitivity to dopamine, short-term low-dose antipsychotic treatment was tested on depressed patients with an expectation of clinical improvement in the supersensitive phase following drug withdrawal. MethodThis was a randomized, double-blind, placebo-controlled study of 48 patients who met criteria for DSM-IV® Major Depressive Disorder, were in a Major Depressive Episode, and had a Hamilton Depression Rating Scale (HAMD) rating of ≥14. Half the participants received 0.25mg oral haloperidol each day for 7 days, after which they received placebo daily for 4 weeks. The other half received placebo throughout the trial. ResultsOne week after stopping the medication, the HAMD ratings of the drug-treated patients fell by 9.96 points, as compared to a reduction of 8.73 points in the placebo-treated patients, when comparing visits 1 and 4. There was no such difference when comparing visits 2 and 4. The differences were not significant, but indicated a trend.One week after the medication was stopped, the Clinical Global Index fell 1.64±0.18 units for the medication-treated patients, compared to 1.12±0.26 units for the placebo group (P=0.05). The regimen was well tolerated. ConclusionsSeven days of an ultra-low dose of 0.25mg haloperidol, followed by withdrawal of haloperidol, resulted in clinical depression improvement greater than placebo and significantly decreased psychomotor retardation, consistent with haloperidol-induced behavioural supersensitivity to dopamine. LimitationsThe sample was small. More patients are needed in a future study.

P4B0104) - Changes of haloperidol(HPL)-induced catalepsy and hypomotility in dopaminergic supersensitivity phase in mice

P4B0104) - Changes of haloperidol(HPL)-induced catalepsy and hypomotility in dopaminergic supersensitivity phase in mice

Dopaminergic supersensitivity: influence of dopamine agonists, cholinergics, anticholinergics, and drugs used for the treatment of tardive dyskinesia.

Single and repeated administration of neuroleptics induce supersensitivity to dopamine agonists like apomorphine and methylphenidate. The degree of this supersensitivity depends on the period of the preceding administration of the neuroleptic. In the development phase additional administration of apomorphine can reverse the hyperdopaminergic behaviour, whereas addition of cholinergic/anticholinergic treatment does not modify the enhanced receptor response. In the supersensitivity phase additional treatment with deanol does not modify the supersensitivity. Pheobarbital, diazepam, and muscimol increase and cis (Z)-flupenthixol decreases the supersensitivity. It is concluded that supersensitivity induced by neuroleptics is time-dependent and that it can be prevented by additional treatment with DA-agonists but not by cholinergic/anticholinergic treatment. In the supersensitivity phase, the syndrome is suppressed by dopamine antagonists but enhanced by GABA-agonists, benzodiazepine and phenobarbital.

Behavioural correlates of modified dopaminergic/anticholinergic responses following chronic treatment with neuroleptic agents of differing activity spectra

An attempt was made to differentiate the mechanisms of action of these “neuroleptic” agents having antidyskinetic properties from the classical neuroleptics by studying the effects of chronic treatment on the responses to a dopamine agonist and cholinergic antagonist. Rats were chronically treated with haloperidol (2 mg/kg i.p.), oxiperomide (8 mg/kg i.p.), pimozide (8 mg/kg p.o.), tiapride (100 mg/kg i.p.), sultopride (100 mg/kg i.p.), sulpiride (100 mg/kg p.o.) and metoclopramide (100 mg/kg i.p.) for 7 consecutive days. On days 1, 3 and 7 after neuroleptic withdrawal rats were assessed for their sensitivity to the stereotypic effects of apomorphine (0.25–1.0 mg/kg s.c.) and the locomotor stimulant effects of dexetimide (0.32–1.25 mg/kg s.c.). A supersensitivity phase to apomorphine, persisting for 1–3 days, was noted in all drug-treated groups and, during this time, the responses to dexetimide were decreased (haloperidol, oxiperomide and pimozide groups), increased (metoclopramide group) or remained similar to control values (sultopride-, sulpiride- and tiapride-treated animals). The responses to dexetimide returned to control values in all treatment groups as the apomorphine sensitivity phase declined. It is suggested that chronic treatment with neuroleptic agents may enhance the sensitivity of those cerebral receptors responsible for mediating the stereotypic effects of apomorphine, and that the relationship between such dopamine function and interacting cholinergic mechanisms may differ for the different groups of neuroleptic agent. However, these differentiations did not directly correlate with the known ability of the neuroleptics to induce or antagonise dyskinetic phenomena.

Dopamine-receptor binding and adenylate-cyclase activity in mouse striatal tissue in the supersensitivity phase after neuroleptic treatment.

The specific binding of 3H-labelled haloperidol (3H-Hal) and the basal and dopamine-stimulated adenylate-cyclase activity in vitro were investigated in mice treated with a single dose or with repeated doses of neuroleptic drugs. These dose regimens are known to induce behavioural supersensitivity and to decrease dopamine synthesis and release a few days after cessation of dosage.

Levels of HVA and DOPAC in mouse corpus striatum in the supersensitivity phase after neuroleptic treatment.

Levels of HVA and DOPAC in mouse corpus striatum in the supersensitivity phase after neuroleptic treatment.

Changes in dopamine synthesis rate in the supersensitivity phase after treatment with a single dose of neuroleptics.

The changes in 14C-dopamine accumulation formed from 14C-tyrosine in mice after treatment with three neuroleptics, cis (Z)-flupenthixol, fluphenazine, and haloperidol, were followed for 6 days. The neuroleptics all changed DA synthesis rate in the same way, initially causing an increase which was followed by a decrease after approximately 3 days. The results are compared with pharmacological results (Christensen et al., 1976) and there seems to be a very close correlation between receptor blockade and increase in DA synthesis on the one hand and on the other hand receptor supersensitivity and decrease in DA synthesis, as was also shown previously for teflutixol (Hyttel, 1975). It is concluded that the changes in receptor activity are always followed by compensatory changes in DA synthesis rate.

On the supersensitivity of dopamine receptors, induced by neuroleptics.

Different neuroleptics caused dopamine receptor blockade (antagonism against methylphenidate-induced compulsive gnawing) for varying lengths of time. When the receptor blockade had expired, supersensitivity to dopamine agonists (occurrence of apomorphine-induced compulsive gnawing and enhancement of methylphenidate-induced gnawing) developed and persisted for varying periods of time. The degree and duration of supersensitivity was related to the degree and duration of the preceding receptor blockade. Inhibition of catecholamine or 5-HT synthesis had no influence on development of supersensitivity. Stimulation with a dopamine agonist, apomorphine, during the period of the development of supersensitivity did not modify the enhanced receptor supersensitivity. A cholinergic-dopaminergic balance was shown to be involved in the manifestation of compulsive behavior during the supersensitivity phase. Tolerance to the dopamine antagonistic effect of a neuroleptic also developed after a single neuroleptic treatment, most likely due to increased sensitivity of the receptors for the dopamine agonist. It is concluded, that the dopamine receptor blockade induced by a single dose of a neuroleptic agent is a dynamic phenomenon which in the course of time is replaced by an increased sensitivity of the receptors to dopamine agonists. Noradrenergic or 5-HT neuron systems do not seem to be involved in the neuroleptic-induced supersensitivity, whereas a dopaminergic-cholinergic balance is operative in the supersensitivity situation.