-
Scientific Reports Nov 2016How do we understand the intentions of other people? There has been a longstanding controversy over whether it is possible to understand others' intentions by simply...
How do we understand the intentions of other people? There has been a longstanding controversy over whether it is possible to understand others' intentions by simply observing their movements. Here, we show that indeed movement kinematics can form the basis for intention detection. By combining kinematics and psychophysical methods with classification and regression tree (CART) modeling, we found that observers utilized a subset of discriminant kinematic features over the total kinematic pattern in order to detect intention from observation of simple motor acts. Intention discriminability covaried with movement kinematics on a trial-by-trial basis, and was directly related to the expression of discriminative features in the observed movements. These findings demonstrate a definable and measurable relationship between the specific features of observed movements and the ability to discriminate intention, providing quantitative evidence of the significance of movement kinematics for anticipating others' intentional actions.
PubMed: 27845434
DOI: 10.1038/srep37036 -
Alimentary Pharmacology & Therapeutics May 2011Loss of response to anti-TNF agents in Crohn's disease is an emerging clinical problem. (Review)
Review
BACKGROUND
Loss of response to anti-TNF agents in Crohn's disease is an emerging clinical problem.
AIM
To review the causes, incidence and management approach of loss of response.
METHODS
A search of medical database (PubMed) and of meetings' proceedings for definitions, causes and incidence of loss of response was carried out. Personal correspondence with principal investigators was conducted to retrieve missing data.
RESULTS
Various definitions of loss of response abound, hampering the ability to assess accurately the magnitude and management of this clinical problem. We propose to distinguish between a clinical worsening on anti-TNF treatment and a true loss of response to anti-TNFs. Accordingly, loss of response to anti-TNFs at 12 months of therapy occurs in 23-46% of patients when judged by dose intensification, or 5-13% when gauged by drug discontinuation rates. The management of loss of response should allow for a period of watchful waiting as quite often the patients' symptoms may resolve without alteration of therapy. If they do not, then identifying the correct mechanism responsible for clinical deterioration is prudent. Once symptoms are ascertained to arise from inflammatory IBD activity, drug level and antidrug antibody measurement can then help distinguish between non-adherence to therapy, immunogenicity and non-immune clearance of anti-TNF, or an un-chequered inflammation despite adequate anti-TNF levels. The latter finding may be best addressed by a switch to another class of immunomodulators, whereas a low drug level should probably be managed by dose intensification or a switch to another anti-TNF.
CONCLUSION
Studies defining how best to translate drug-level monitoring and other mechanistic considerations into clinical decisions are urgently needed.
Topics: Anti-Inflammatory Agents; Crohn Disease; Dose-Response Relationship, Drug; Humans; Immunologic Factors; Treatment Failure; Tumor Necrosis Factor-alpha; Watchful Waiting
PubMed: 21366636
DOI: 10.1111/j.1365-2036.2011.04612.x -
Entropy (Basel, Switzerland) Dec 2021The thermocontextual interpretation (TCI) is an alternative to the existing interpretations of physical states and time. The prevailing interpretations are based on...
The thermocontextual interpretation (TCI) is an alternative to the existing interpretations of physical states and time. The prevailing interpretations are based on assumptions rooted in classical mechanics, the logical implications of which include determinism, time symmetry, and a paradox: determinism implies that effects follow causes and an arrow of causality, and this conflicts with time symmetry. The prevailing interpretations also fail to explain the empirical irreversibility of wavefunction collapse without invoking untestable and untenable metaphysical implications. They fail to reconcile nonlocality and relativistic causality without invoking superdeterminism or unexplained superluminal correlations. The TCI defines a system's state with respect to its actual surroundings at a positive ambient temperature. It recognizes the existing physical interpretations as special cases which either define a state with respect to an absolute zero reference (classical and relativistic states) or with respect to an equilibrium reference (quantum states). Between these special case extremes is where thermodynamic irreversibility and randomness exist. The TCI distinguishes between a system's internal time and the reference time of relativity and causality as measured by an external observer's clock. It defines system time as a complex property of state spanning both reversible mechanical time and irreversible thermodynamic time. Additionally, it provides a physical explanation for nonlocality that is consistent with relativistic causality without hidden variables, superdeterminism, or "spooky action".
PubMed: 34946011
DOI: 10.3390/e23121705 -
Clinical Cancer Research : An Official... Feb 2023Watchful waiting (WW) can be considered for patients with metastatic clear-cell renal cell carcinoma (mccRCC) with good or intermediate prognosis, especially those with...
PURPOSE
Watchful waiting (WW) can be considered for patients with metastatic clear-cell renal cell carcinoma (mccRCC) with good or intermediate prognosis, especially those with <2 International Metastatic RCC Database Consortium criteria and ≤2 metastatic sites [referred to as watch and wait ("W&W") criteria]. The IMaging PAtients for Cancer drug SelecTion-Renal Cell Carcinoma study objective was to assess the predictive value of [18F]FDG PET/CT and [89Zr]Zr-DFO-girentuximab PET/CT for WW duration in patients with mccRCC.
EXPERIMENTAL DESIGN
Between February 2015 and March 2018, 48 patients were enrolled, including 40 evaluable patients with good (n = 14) and intermediate (n = 26) prognosis. Baseline contrast-enhanced CT, [18F]FDG and [89Zr]Zr-DFO-girentuximab PET/CT were performed. Primary endpoint was the time to disease progression warranting systemic treatment. Maximum standardized uptake values (SUVmax) were measured using lesions on CT images coregistered to PET/CT. High and low uptake groups were defined on the basis of median geometric mean SUVmax of RECIST-measurable lesions across patients.
RESULTS
The median WW time was 16.1 months [95% confidence interval (CI): 9.0-31.7]. The median WW period was shorter in patients with high [18F]FDG tumor uptake than those with low uptake (9.0 vs. 36.2 months; HR, 5.6; 95% CI: 2.4-14.7; P < 0.001). Patients with high [89Zr]Zr-DFO-girentuximab tumor uptake had a median WW period of 9.3 versus 21.3 months with low uptake (HR, 1.7; 95% CI: 0.9-3.3; P = 0.13). Patients with "W&W criteria" had a longer median WW period of 21.3 compared with patients without: 9.3 months (HR, 1.9; 95% CI: 0.9-3.9; Pone-sided = 0.034). Adding [18F]FDG uptake to the "W&W criteria" improved the prediction of WW duration (P < 0.001); whereas [89Zr]Zr-DFO-girentuximab did not (P = 0.53).
CONCLUSIONS
In patients with good- or intermediate-risk mccRCC, low [18F]FDG uptake is associated with prolonged WW. This study shows the predictive value of the "W&W criteria" for WW duration and shows the potential of [18F]FDG-PET/CT to further improve this.
Topics: Humans; Carcinoma, Renal Cell; Positron Emission Tomography Computed Tomography; Fluorodeoxyglucose F18; Radioisotopes; Zirconium; Watchful Waiting; Prognosis; Radiopharmaceuticals
PubMed: 36394882
DOI: 10.1158/1078-0432.CCR-22-0921 -
The Cochrane Database of Systematic... May 2015Melanoma is the leading cause of skin cancer-associated mortality. The vast majority of newly diagnosed melanomas are confined to the primary cutaneous site. Surgery... (Review)
Review
BACKGROUND
Melanoma is the leading cause of skin cancer-associated mortality. The vast majority of newly diagnosed melanomas are confined to the primary cutaneous site. Surgery represents the mainstay of melanoma treatment. Treatment strategies include wide excision of the primary tumour and sentinel lymph node biopsy (SLNB) to assess the status of the regional nodal basin(s). SLNB has become an important component of initial melanoma management providing accurate disease staging.
OBJECTIVES
To assess the effects and safety of SLNB followed by completion lymph node dissection (CLND) for the treatment of localised primary cutaneous melanoma.
SEARCH METHODS
We searched the following databases up to February 2015: the Cochrane Skin Group Specialised Register, the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library (2015, Issue 1), MEDLINE (from 1946), EMBASE (from 1974), and LILACS ((Latin American and Caribbean Health Science Information database, from 1982). We also searched the following from inception: African Index Medicus, IndMED of India, Index Medicus for the South-East Asia Region, and six trials registers. We checked the reference lists of included and excluded studies for further references to relevant randomised controlled trials (RCTs). We searched ISI Web of Science Conference Proceedings from inception to February 2015, and we scanned the abstracts of major dermatology and oncology conference proceedings up to 2015.
SELECTION CRITERIA
Two review authors independently assessed all RCTs comparing SLNB followed by CLND for the treatment of primary localised cutaneous melanoma for inclusion. Primary outcome measures were overall survival and rate of treatment complications and side effects.
DATA COLLECTION AND ANALYSIS
Two review authors independently extracted and analysed data on survival and recurrence, assessed risk of bias, and collected adverse effect information from included trials.
MAIN RESULTS
We identified and included a single eligible trial comparing SLNB with observation and published in eight different reports (from 2005 to 2014) with 2001 participants. This did not report on our first primary outcome of overall survival. The study did report on the rate of treatment complications. Our secondary outcomes of disease-specific and disease-free survival, local recurrence and distant metastases were reported. There were 1347 participants in the intermediate-thickness melanoma group and 314 in the thick melanoma group.With regard to treatment complications, short-term surgical morbidity (30 days) in 1735 participants showed no difference between SLNB and observation (risk ratio [RR] 1.11; 95% confidence interval [CI] 0.9 to 1.37) for wide excision of the tumour site but favoured observation for complications related to the regional nodal basin (RR 14.36; 95% CI 6.74 to 30.59).The study did not report the actual 10-year melanoma-specific survival rate for all included participants. Instead, melanoma-specific survival rates for each group of participants: intermediate-thickness melanoma (defined as 1.2 to 3.5 mm) and thick melanomas (defined as 3.50 mm or more) was reported.In the intermediate-thickness melanoma group there was no statistically significant difference in disease-specific survival between study groups at 10 years (81.4 ± 1.5% versus 78.3 ± 2.0%, hazard ratio [HR] 0.84; 95% CI 0.65 to 1.09). In the thick melanoma group, again there was no statistically significant difference in disease-specific survival between study groups at 10 years (58.9.3 ± 4.1% versus 64.4 ± 4.6%, HR 1.12; 95% CI 0.77 to 1.64). Combining these groups there was some heterogeneity (I² = 34%) but the total HR was not statistically significant (HR 0.92; 95% CI 0.74 to 1.14). This study failed to show any difference for its stated primary outcome.The summary estimate for disease-free survival at 10 years favoured SLNB over observation in participants with intermediate-thickness and thick melanomas (HR 0.75; 95% CI 0.63 to 0.89).With regard to the rate of local and regional recurrence as the site of first recurrence, a benefit of SLNB uniformly existed in both groups of participants with intermediate-thickness and thick melanomas (RR 0.56; 95% CI 0.45 to 0.69). This is in contrast with a uniformly unfavourable effect of SLNB with regard to the rate of distant metastases as site of first recurrence, in both groups of participants with intermediate-thickness and thick melanomas (HR 1.33; 95% CI 1.03 to 1.72).
AUTHORS' CONCLUSIONS
We contacted the trial authors querying the lack of data on overall survival which was the primary outcome of their important study. They stated "there are numerous additional analyses that have yet to be reported for the trial". We expect that overall survival data will be available in a future update of this review.Disease-free survival and rate of local and regional recurrence favoured SLNB in both groups of participants with intermediate-thickness and thick melanomas but short-term surgical morbidity was higher in the SLNB group, especially with regard to complications in the nodal basin.The evidence for the outcomes of interest in this review is of low quality due to the risk of bias and imprecision of the estimated effects. Further research may have an important impact on our estimate of the effectiveness of SLNB in managing primary localised cutaneous melanoma. Currently this evidence is not sufficient to document a benefit of SLNB when compared to observation in individuals with primary localised cutaneous melanoma.
Topics: Disease-Free Survival; Humans; Lymph Node Excision; Melanoma; Randomized Controlled Trials as Topic; Sentinel Lymph Node Biopsy; Skin Neoplasms; Survival Rate; Watchful Waiting; Melanoma, Cutaneous Malignant
PubMed: 25978975
DOI: 10.1002/14651858.CD010307.pub2 -
Current Urology Reports Jul 2017Previously considered an absolute contraindication, the use of testosterone therapy in men with prostate cancer has undergone an important paradigm shift. Recent data... (Review)
Review
PURPOSE OF REVIEW
Previously considered an absolute contraindication, the use of testosterone therapy in men with prostate cancer has undergone an important paradigm shift. Recent data has changed the way we approach the treatment of testosterone deficiency in men with prostate cancer. In the current review, we summarize and analyze the literature surrounding effects of testosterone therapy on patients being treated in an active surveillance protocol as well as following definitive treatment for prostate cancer.
RECENT FINDINGS
The conventional notion that defined the relationship between increasing testosterone and prostate cancer growth was based on limited studies and anecdotal case reports. Contemporary evidence suggests testosterone therapy in men with testosterone deficiency does not increase prostate cancer risk or the chances of more aggressive disease at prostate cancer diagnosis. Although the studies are limited, men who received testosterone therapy for localized disease did not have higher rates of recurrences or worse clinical outcomes. Current review of the literature has not identified adverse progression events for patients receiving testosterone therapy while on active surveillance/watchful waiting or definitive therapies. The importance of negative effects of testosterone deficiency on health and health-related quality of life measures has pushed urologists to re-evaluate the role testosterone plays in prostate cancer. This led to a paradigm shift that testosterone therapy might in fact be a viable option for a select group of men with testosterone deficiency and a concurrent diagnosis of prostate cancer.
Topics: Androgens; Contraindications, Drug; Disease Progression; Humans; Hypogonadism; Male; Prostatic Neoplasms; Quality of Life; Testosterone; Watchful Waiting
PubMed: 28589395
DOI: 10.1007/s11934-017-0695-6 -
Journal of Vascular Surgery Sep 2018The optimal catheter-directed therapy for femoropopliteal in-stent restenosis (ISR) remains controversial with limited durability. The natural history of untreated ISR...
OBJECTIVE
The optimal catheter-directed therapy for femoropopliteal in-stent restenosis (ISR) remains controversial with limited durability. The natural history of untreated ISR is not well characterized. We evaluated the midterm outcomes of patients with asymptomatic isolated femoropopliteal ISR who were observed under a surveillance program.
METHODS
Patients treated with isolated femoropopliteal stents from January 2009 to December 2013 were retrospectively investigated for the development of ISR. ISR was classified on the basis of duplex ultrasound criteria, with >50% defined as peak systolic velocity (PSV) twice that of the normal vessel and >75% as PSV >400 cm/s or four times the normal PSV. Asymptomatic patients with ISR of >50% were tracked for progression to high-grade (>75%) stenosis, occlusion, need for reintervention, and amputation.
RESULTS
Asymptomatic ISR of >50% was identified in 62 (15.3%) of 402 patients with isolated femoropopliteal stents. The mean time for development of ISR was 22.1 (±20.1) months. The mean age was 72 (±9.7) years, and 34 (55.7%) patients were female. Thirty-one (50%) patients were diabetic, 18 (29.1%) were smokers, and 8 (12.9%) had chronic kidney disease. Indications for treatment were claudication in 49 (79.0%), tissue loss in 9 (14.5%), and rest pain in 4 (6.4%) patients. TransAtlantic Inter-Society Consensus (TASC) A lesions were treated in 13 (21%) patients, TASC B lesions in 24 (38.7%), and TASC C lesions in 25 (40.3%). Three-vessel runoff was identified in 25 (40.3%) patients, two-vessel runoff in 18 (29.0%), and one-vessel runoff in 19 (30.6%). Under surveillance, ISR of >50% progressed to >75% or occlusion in 20 (32.3%) patients. The mean time to progression was 17.4 months, and the mean overall follow-up was 33.1 months. Reintervention was required in 22 (35.0%) patients, with an average of 1.95 (range, 1-4) interventions per patient. Reintervention was undertaken in 19 (86%) patients for claudication and in 3 (18%) patients for critical limb ischemia. One patient required an amputation despite previous reintervention for progression. Progression to >75% stenosis was predictive of need for reintervention (P = .004).
CONCLUSIONS
Under a surveillance program, asymptomatic patients with femoropopliteal ISR of >50% may be observed with a low risk of limb loss. Given the slow rate of progression and the poor durability of reintervention, surveillance with delayed intervention may be warranted.
Topics: Aged; Arterial Occlusive Diseases; Comorbidity; Constriction, Pathologic; Disease Progression; Female; Femoral Artery; Humans; Limb Salvage; Male; Peripheral Arterial Disease; Popliteal Artery; Recurrence; Retrospective Studies; Stents; Treatment Outcome; Ultrasonography, Doppler, Duplex; Vascular Patency; Watchful Waiting
PubMed: 30144908
DOI: 10.1016/j.jvs.2018.01.030 -
Scientific Reports Jan 2022Visual memory schemas (VMS) are two-dimensional memorability maps that capture the most memorable regions of a given scene, predicting with a high degree of consistency...
Visual memory schemas (VMS) are two-dimensional memorability maps that capture the most memorable regions of a given scene, predicting with a high degree of consistency human observer's memory for the same images. These maps are hypothesized to correlate with a mental framework of knowledge employed by humans to encode visual memories. In this study, we develop a generative model we term 'MEMGAN' constrained by extracted visual memory schemas that generates completely new complex scene images that vary based on their degree of predicted memorability. The generated populations of high and low memorability images are then evaluated for their memorability using a human observer experiment. We gather VMS maps for these generated images from participants in the memory experiment and compare these with the intended target VMS maps. Following the evaluation of observers' memory performance through both VMS-defined memorability and hit rate, we find significantly superior memory performance by human observers for the highly memorable generated images compared to poorly memorable. Implementing and testing a construct from cognitive science allows us to generate images whose memorability we can manipulate at will, as well as providing a tool for further study of mental schemas in humans.
Topics: Photic Stimulation
PubMed: 35091559
DOI: 10.1038/s41598-022-05623-y -
The Cochrane Database of Systematic... Jul 2021Stem cell therapy (SCT) has been proposed as an alternative treatment for dilated cardiomyopathy (DCM), nonetheless its effectiveness remains debatable. (Meta-Analysis)
Meta-Analysis
BACKGROUND
Stem cell therapy (SCT) has been proposed as an alternative treatment for dilated cardiomyopathy (DCM), nonetheless its effectiveness remains debatable.
OBJECTIVES
To assess the effectiveness and safety of SCT in adults with non-ischaemic DCM.
SEARCH METHODS
We searched CENTRAL in the Cochrane Library, MEDLINE, and Embase for relevant trials in November 2020. We also searched two clinical trials registers in May 2020.
SELECTION CRITERIA
Eligible studies were randomized controlled trials (RCT) comparing stem/progenitor cells with no cells in adults with non-ischaemic DCM. We included co-interventions such as the administration of stem cell mobilizing agents. Studies were classified and analysed into three categories according to the comparison intervention, which consisted of no intervention/placebo, cell mobilization with cytokines, or a different mode of SCT. The first two comparisons (no cells in the control group) served to assess the efficacy of SCT while the third (different mode of SCT) served to complement the review with information about safety and other information of potential utility for a better understanding of the effects of SCT.
DATA COLLECTION AND ANALYSIS
Two review authors independently screened all references for eligibility, assessed trial quality, and extracted data. We undertook a quantitative evaluation of data using random-effects meta-analyses. We evaluated heterogeneity using the I² statistic. We could not explore potential effect modifiers through subgroup analyses as they were deemed uninformative due to the scarce number of trials available. We assessed the certainty of the evidence using the GRADE approach. We created summary of findings tables using GRADEpro GDT. We focused our summary of findings on all-cause mortality, safety, health-related quality of life (HRQoL), performance status, and major adverse cardiovascular events.
MAIN RESULTS
We included 13 RCTs involving 762 participants (452 cell therapy and 310 controls). Only one study was at low risk of bias in all domains. There were many shortcomings in the publications that did not allow a precise assessment of the risk of bias in many domains. Due to the nature of the intervention, the main source of potential bias was lack of blinding of participants (performance bias). Frequently, the format of the continuous data available was not ideal for use in the meta-analysis and forced us to seek strategies for transforming data in a usable format. We are uncertain whether SCT reduces all-cause mortality in people with DCM compared to no intervention/placebo (mean follow-up 12 months) (risk ratio (RR) 0.84, 95% confidence interval (CI) 0.54 to 1.31; I² = 0%; studies = 7, participants = 361; very low-certainty evidence). We are uncertain whether SCT increases the risk of procedural complications associated with cells injection in people with DCM (data could not be pooled; studies = 7; participants = 361; very low-certainty evidence). We are uncertain whether SCT improves HRQoL (standardized mean difference (SMD) 0.62, 95% CI 0.01 to 1.23; I² = 72%; studies = 5, participants = 272; very low-certainty evidence) and functional capacity (6-minute walk test) (mean difference (MD) 70.12 m, 95% CI -5.28 to 145.51; I² = 87%; studies = 5, participants = 230; very low-certainty evidence). SCT may result in a slight functional class (New York Heart Association) improvement (data could not be pooled; studies = 6, participants = 398; low-certainty evidence). None of the included studies reported major adverse cardiovascular events as defined in our protocol. SCT may not increase the risk of ventricular arrhythmia (data could not be pooled; studies = 8, participants = 504; low-certainty evidence). When comparing SCT to cell mobilization with granulocyte-colony stimulating factor (G-CSF), we are uncertain whether SCT reduces all-cause mortality (RR 0.46, 95% CI 0.16 to 1.31; I² = 39%; studies = 3, participants = 195; very low-certainty evidence). We are uncertain whether SCT increases the risk of procedural complications associated with cells injection (studies = 1, participants = 60; very low-certainty evidence). SCT may not improve HRQoL (MD 4.61 points, 95% CI -5.62 to 14.83; studies = 1, participants = 22; low-certainty evidence). SCT may improve functional capacity (6-minute walk test) (MD 140.14 m, 95% CI 119.51 to 160.77; I² = 0%; studies = 2, participants = 155; low-certainty evidence). None of the included studies reported MACE as defined in our protocol or ventricular arrhythmia. The most commonly reported outcomes across studies were based on physiological measures of cardiac function where there were some beneficial effects suggesting potential benefits of SCT in people with non-ischaemic DCM. However, it is unclear if this intermediate effects translates into clinical benefits for these patients. With regard to specific aspects related to the modality of cell therapy and its delivery, uncertainties remain as subgroup analyses could not be performed as planned, making it necessary to wait for the publication of several studies that are currently in progress before any firm conclusion can be reached.
AUTHORS' CONCLUSIONS
We are uncertain whether SCT in people with DCM reduces the risk of all-cause mortality and procedural complications, improves HRQoL, and performance status (exercise capacity). SCT may improve functional class (NYHA), compared to usual care (no cells). Similarly, when compared to G-CSF, we are also uncertain whether SCT in people with DCM reduces the risk of all-cause mortality although some studies within this comparison observed a favourable effect that should be interpreted with caution. SCT may not improve HRQoL but may improve to some extent performance status (exercise capacity). Very low-quality evidence reflects uncertainty regarding procedural complications. These suggested beneficial effects of SCT, although uncertain due to the very low certainty of the evidence, are accompanied by favourable effects on some physiological measures of cardiac function. Presently, the most effective mode of administration of SCT and the population that could benefit the most is unclear. Therefore, it seems reasonable that use of SCT in people with DCM is limited to clinical research settings. Results of ongoing studies are likely to modify these conclusions.
Topics: Arrhythmias, Cardiac; Bias; Cardiomyopathy, Dilated; Cause of Death; Granulocyte Colony-Stimulating Factor; Humans; Placebos; Quality of Life; Randomized Controlled Trials as Topic; Severity of Illness Index; Stem Cell Transplantation; Walk Test; Watchful Waiting
PubMed: 34286511
DOI: 10.1002/14651858.CD013433.pub2 -
Entropy (Basel, Switzerland) Oct 2022Core quantum postulates including the superposition principle and the unitarity of evolutions are natural and strikingly simple. I show that-when supplemented with a... (Review)
Review
Core quantum postulates including the superposition principle and the unitarity of evolutions are natural and strikingly simple. I show that-when supplemented with a limited version of predictability (captured in the textbook accounts by the repeatability postulate)-these core postulates can account for all the symptoms of classicality. In particular, both objective classical reality and elusive information about reality arise, via quantum Darwinism, from the quantum substrate. This approach shares with the Relative State Interpretation of Everett the view that collapse of the wavepacket reflects perception of the state of the rest of the Universe to the state of observer's records. However, our "let quantum be quantum" approach poses questions absent in Bohr's Copenhagen Interpretation that relied on the preexisting classical domain. Thus, one is now forced to seek preferred, predictable, hence effectively classical but ultimately quantum states that allow observers keep reliable records. Without such relative states are simply "too relative", and the ensuing makes it difficult to identify events (e.g., measurement outcomes). Moreover, universal validity of quantum theory raises the issue of , pk=|ψk|2, relating probabilities and amplitudes (that is simply postulated in textbooks). Last not least, even preferred pointer states (defined by -nvironment-duced super)-are still quantum. Therefore, unlike classical states that exist objectively, quantum states of an individual system cannot be found out by an initially ignorant observer through direct measurement without being disrupted. So, to complete the 'quantum theory of the classical' one must identify and explain how the information about objectively existing states can appear to be essentially inconsequential for them (as it does for states in Newtonian physics) and yet matter in other settings (e.g., thermodynamics). I show how the mathematical structure of quantum theory supplemented by the only uncontroversial measurement postulate (that demands immediate repeatability-hence, predictability) leads to preferred states. These correspond to measurement outcomes. Their stability is a prerequisite for objective existence of effectively classical states and for events such as quantum jumps. Events at hand, one can now enquire about their probability-the probability of a pointer state (or of a measurement record). I show that the symmetry of entangled states- or -implies Born's rule. Envariance also accounts for the loss of phase coherence between pointer states. Thus, decoherence can be traced to symmetries of entanglement and understood without its usual tool-reduced density matrices. A simple and manifestly noncircular derivation of pk=|ψk|2 follows. Monitoring of the system by its environment in course of decoherence typically leaves behind multiple copies of its pointer states in the environment. Only pointer states can survive decoherence and can spawn such plentiful information-theoretic progeny. This allows observers to use -to find out pointer states indirectly, leaving systems of interest untouched. Quantum Darwinism shows how epistemic and ontic (coexisting in quantum state) separate into robust objective existence of pointer states and detached information about them, giving rise to -composite objects with system of interest in the core and multiple records of its pointer states in the halo comprising of environment subsystems (e.g., photons) which disseminates that information throughout the Universe.
PubMed: 36359613
DOI: 10.3390/e24111520