{{Short description|Canadian theoretical physicist (1940–2017)}} {{Infobox scientist | honorific_prefix = | honorific_suffix = | native_name = | native_name_lang = | image = Helen_S_Freedhoff.jpg | image_size = | image_upright = | alt = Photo of Helen Freedhoff | caption = ''Helen Freedhoff, 1961'' | birth_name = Helen Sarah Goodman | birth_date = {{birth date|1940|1|9}} | birth_place = Toronto, Ontario | death_date = {{death date and age|2017|6|10|1940|1|9}} | death_place = Muskoka, Ontario | death_cause = | resting_place = | resting_place_coordinates = <!--{{coord|LAT|LONG|type:landmark|display=inline,title}}--> | other_names = | residence = | citizenship = | nationality = | fields = Theoretical physics | workplaces = {{plainlist| * Imperial College, London * York University, Toronto }} | patrons = | education = Harbord Collegiate Institute | alma_mater = University of Toronto | thesis_title = Theory of dipole-dipole interaction in coherent radiation processes | thesis_url = http://search.library.utoronto.ca/details?266593 | thesis_year = 1965 | doctoral_advisor = <!--(or | doctoral_advisors = )--> | academic_advisors = | doctoral_students = | notable_students = Terry Rudolph (PBR theorem) | known_for = {{plainlist| * Theoretical study of atom-photon interaction * First woman physics professor at York University }} | influences = | influenced = | awards = | spouse = Stephen Freedhoff | children = {{plainlist| * Michal Freedhoff * Yoni Freedhoff }} | signature = <!--(filename only)--> | signature_alt = | website = <!--{{URL|www.example.com}}--> | footnotes = }}
'''Helen Sarah Freedhoff''' (January 9, 1940 – June 10, 2017) was a Canadian theoretical physicist who studied the interaction of light with atoms. She gained her doctorate at the University of Toronto in 1965 and completed a postdoctoral fellowship at Imperial College in London. Freedhoff was the first woman appointed as a physics professor at York University in Toronto, and is believed to have been the only woman professor of theoretical physics in Canada at the time.
==Early life and education== Helen Freedhoff was born Helen Sarah Goodman in Toronto on 9 January 1940.<ref name="Weighty Matters obit" /><ref name="Obit Globe and Mail" /> Her parents were Ethel (Kohl) and Sholom Goodman and she had two brothers, David and Irving.<ref name="Weighty Matters obit">{{cite web|last1=Freedhoff|first1=Yoni|title=Remembering My Mother (And Why I Won't Be Around As Much For a While)|url=http://www.weightymatters.ca/2017/06/remembering-my-mother-and-why-ill-be.html|website=www.weightymatters.ca|access-date=17 June 2017}}</ref> Her nickname was "Henchy".<ref name="Harbord reunion" /><ref name="Weighty Matters obit" />
In 1957 she graduated from Harbord Collegiate Institute, a downtown public high school with predominantly Jewish students and a history of many earlier notable alumni.<ref name="Harbord reunion" /> Pursuing an academic career in science was unusual for a woman in North America in the post-war 1950s, where young men entered science in great numbers and women were pressured to make way.<ref name="Rossiter">{{cite book|last1=Rossiter|first1=Margaret W.|title=Women Scientists in America: Before Affirmative Action, 1940- 1972|date=1995|publisher=Johns Hopkins University Press|location=Baltimore, MD}}</ref> At Harbord, however, Freedhoff did not face opposition, recalling "In high school it never occurred to me that I would have to play dumb to get dates. Nobody ever really discouraged me. The teachers really encouraged me, and nobody taught me that there was anything wrong with having a career".<ref name="Harbord reunion">{{cite news|last1=Bimman|first1=Abigail|title=50-year reunion for Harbord Collegiate grads|url=http://harbordclub.com/57/57.htm|access-date=17 June 2017|work=The Canadian Jewish News|date=30 August 2007|archive-date=27 March 2019|archive-url=https://web.archive.org/web/20190327092715/http://harbordclub.com/57/57.htm|url-status=dead}}</ref>
Freedhoff enrolled in the Mathematics, Physics, and Chemistry stream at the University of Toronto, one of around 10-15 women among 120 first year students.<ref name="Prentice 2006" /> Originally intending to study mathematics, she found that she preferred physics.<ref name="Heap 2005">{{cite book |author1-link=Ruby Heap |last1=Heap|first1=Ruby|last2=Millar|first2=Wyn|last3=Smyth|first3=Elizabeth M|title=Learning to practise: professional education in historical and contemporary perspective|date=2005|publisher=University of Ottawa Press|location=Ottawa|isbn=978-0-7766-0605-7|language=English|oclc=243568253}}</ref> Freedhoff was the only woman in her year to major in physics, graduating with the highest marks and being awarded the Governor General's Gold Medal.<ref name="Prentice 2006" /> She did not feel professionally disadvantaged by being the only woman, and felt it could be an advantage to stand out.<ref name="Heap 2005" />
Freedhoff had summer jobs in Harold Johns' biophysics lab.<ref name="Heap 2005" /> Johns was a pioneer of medical biophysics, developing cobalt radiation therapy for cancer in the 1940s.<ref name="Johns bio">{{cite web|title=H.E. Johns|url=https://cns-snc.ca/media/history/pioneers/harold_johns/hejohns.html|website=cns-snc.ca|publisher=Canadian Nuclear Society|access-date=17 June 2017|archive-date=16 March 2016|archive-url=https://web.archive.org/web/20160316091048/https://cns-snc.ca/media/history/pioneers/harold_johns/hejohns.html}}</ref> Although she enjoyed her time there, and was interested in the work Harry Welsh was doing on lasers, laboratory work was not her forte.<ref name="Heap 2005" /> Freedhoff was inspired by Jan Van Kranendonk, a theoretical physicist,<ref name="JVK bio">{{cite web|title=In memoriam: Jan Van Kranendonk — Department of Physics|url=https://www.physics.utoronto.ca/people/in-memoriam/jan-van-kranendonk|website=www.physics.utoronto.ca|publisher=University of Toronto|access-date=17 June 2017|language=en|archive-date=11 August 2017|archive-url=https://web.archive.org/web/20170811183506/https://www.physics.utoronto.ca/people/in-memoriam/jan-van-kranendonk}}</ref> who encouraged her to undertake postgraduate studies under his supervision.<ref name="Heap 2005" /> From then on, she dedicated her career to what she has described as "the exhilaration of scientific research"<ref name="Book review">{{cite journal|last1=Freedhoff|first1=Helen|title=Gerhard Herzberg: An Illustrious Life in Science by Boris Stoicheff (review)|journal=University of Toronto Quarterly|date=Winter 2003|volume=73|issue=1|pages=305–307|url=http://muse.jhu.edu/article/517917/pdf|access-date=17 June 2017}}</ref> and teaching. "Basic science," she wrote, "is indeed a high form of culture, no less so than music or literature because it is also useful".<ref name="Book review" />
==Career and research== Although women gained nearly 20% of the doctoral degrees awarded in physics by the University of Toronto between 1890 and 1933, Freedhoff was only the second woman to gain a PhD in physics after 1934 at the University of Toronto, following Olga Mracek Mitchell in 1962.<ref name="Prentice 2006" /> Freedhoff earned her PhD in 1965 with a dissertation titled ''Theory of dipole-dipole interaction in coherent radiation processes''.<ref name="Freedhoff dissertation">{{cite book|last1=Freedhoff|first1=Helen Sarah|title=Theory of dipole-dipole interaction in coherent radiation processes|date=1965|publisher=University of Toronto|location=Toronto|url=http://search.library.utoronto.ca/details?266593|access-date=17 June 2017}}</ref> Women were awarded only 5% of the physics doctorates at the University of Toronto between 1960 and 1975.<ref name="Prentice 2006">{{cite journal|last1=Prentice|first1=Alison|title=A Blackboard in Her Kitchen: Women and Physics at the University of Toronto|journal=Scientia Canadensis|date=2006|volume=292|pages=17–44|url=https://www.erudit.org/fr/revues/scientia/2006-v29-n2-scientia3150/800518ar.pdf|access-date=17 June 2017}}</ref>
Freedhoff was awarded a postdoctoral fellowship by the National Research Council of Canada, working at Imperial College, London, from 1965 to 1967.<ref name="Heap 2005" /><ref name="Freedhoff - metal atoms - 1967">{{cite journal|last1=Freedhoff|first1=Helen S.|title=Molecular features in the spectra of atoms trapped in inert gas matrices|journal=Proceedings of the Physical Society|date=1967|volume=92|issue=2|pages=505–510|doi=10.1088/0370-1328/92/2/328|language=en|issn=0370-1328|bibcode=1967PPS....92..505F}}</ref> She studied means of identifying molecular features of atoms trapped in metals with spectroscopy, work which was partly sponsored by the United States Air Force Office of Scientific Research.<ref name="Freedhoff - metal atoms - 1967" />
While in London, she wrote to the physics department at York University in Toronto enquiring about job opportunities.<ref name="Prentice 2006" /> In 1967, she was appointed assistant professor in physics there, the university's first woman professor in physics and believed to be Canada's only woman professor in theoretical physics at that time.<ref name="Physics in Canada 1967">{{cite journal|title=Canadian physisicts|journal=Physics in Canada|date=Autumn 1967|volume=23|issue=4|page=43|url=https://www.cap.ca/onlineforms/temp_PiC_archive/1967-v23-n4.pdf|access-date=17 June 2017}}</ref><ref name="Heap 2005" /><ref name="Stephen Freedhoff bio" />
Other than a sabbatical year at the Department of Physics of Technion, the Israel Institute of Technology in Haifa from 1986,<ref name="Sabbatical mention">{{cite journal|title=Canadian physicists|journal=Physics in Canada|date=January 1986|volume=42|issue=1|page=33|url=https://www.cap.ca/onlineforms/temp_PiC_archive/1986-v42-n1.pdf|access-date=17 June 2017}}</ref><ref name="Freedhoff - Israel-authored paper 1987">{{cite journal|last1=Freedhoff|first1=H. S.|title=Cooperative spontaneous emission by a fully inverted array of N atoms: small-sample limit|journal=Journal of Physics B: Atomic and Molecular Physics|date=1987|volume=20|issue=2|pages=285–293|doi=10.1088/0022-3700/20/2/012|language=en|issn=0022-3700|bibcode=1987JPhB...20..285F}}</ref> Freedhoff remained at York University until her retirement in 2005, having published over 40 research papers.<ref name="Retirement mention">{{cite web|title=Priorities for future hiring|url=http://www.math.yorku.ca/Chair/requests04.htm|website=www.math.yorku.ca|publisher=York University|access-date=17 June 2017}}</ref><ref name="Publications">{{cite web|title=Freedhoff, HS: Query Results from the Physics Database|url=http://adsabs.harvard.edu/cgi-bin/nph-abs_connect?db_key=PHY&qform=PHY&aut_logic=OR&author=freedhoff,+h&ned_query=YES&sim_query=YES&start_mon=&start_year=&end_mon=&end_year=&ttl_logic=OR&title=&txt_logic=OR&text=&nr_to_return=20&start_nr=1&jou_pick=ALL&ref_stems=&data_and=ALL&group_and=ALL&start_entry_day=&start_entry_mon=&start_entry_year=&end_entry_day=&end_entry_mon=&end_entry_year=&min_score=&sort=NDATE&data_type=SHORT&aut_syn=YES&ttl_syn=YES&txt_syn=YES&aut_wt=1.0&ttl_wt=0.3&txt_wt=3.0&aut_wgt=YES&obj_wgt=YES&ttl_wgt=YES&txt_wgt=YES&ttl_sco=YES&txt_sco=YES&version=1|publisher=Harvard University|access-date=17 June 2017}}</ref> She also collaborated with physicists in Australia,<ref name="York Uni profile">{{cite web|title=Faculty Members - Freedhoff|url=http://www.physics.yorku.ca/index.php/who-we-are/graduate-faculty-by-research-area/55-freedhoff|website=www.physics.yorku.ca|publisher=York University|access-date=17 June 2017|language=en-gb|archive-date=13 March 2020|archive-url=https://web.archive.org/web/20200313115553/https://www.physics.yorku.ca/who-we-are/graduate-faculty-by-research-area/55-freedhoff|url-status=dead}}</ref> which led to Terry Rudolph undertaking his doctoral studies under Freedhoff's supervision in the 1990s.<ref name="Rudolph dissertation">{{cite book|last1=Rudolph|first1=T|title=Dressing an atom in a field of many colors|date=1998|publisher=York University|location=Toronto|url=http://www.collectionscanada.gc.ca/obj/s4/f2/dsk2/tape15/PQDD_0028/NQ33548.pdf|access-date=17 June 2017}}</ref> He is a professor of physics at Imperial College,<ref name="Rudolph - Imperial">{{cite web|title=Home - Professor Terence Rudolph|url=http://www.imperial.ac.uk/people/t.rudolph|website=www.imperial.ac.uk|publisher=Imperial College|access-date=17 June 2017}}</ref> and together with Matthew Pusey and Jonathan Barrett, one of the developers of the PBR theorem, an important development in quantum mechanics named for its three authors.<ref name="Reich - Nature">{{cite journal|last1=Samuel Reich|first1=Eugenie|title=Quantum theorem shakes foundations|journal=Nature|date=17 November 2011|doi=10.1038/nature.2011.9392|url=http://www.nature.com/news/quantum-theorem-shakes-foundations-1.9392|access-date=17 June 2017|url-access=subscription}}</ref> Rudolph, who is Erwin Schrödinger's grandson,<ref name="Ryan 2013">{{cite news|last1=Ryan|first1=Greg|title=Searching for the Man Behind the Cat|url=http://brooklynrail.org/2013/06/books/searching-for-the-man-behind-the-cat|access-date=17 June 2017|work=brooklynrail.org|issue=June|date=3 June 2013}}</ref> delivered one of the eulogies at Freedhoff's funeral.<ref name="Eulogies">{{cite web|last1=Freedhoff|first1=Yoni|title=Remembering Helen Freedhoff (1940-2017)|url=https://www.youtube.com/watch?v=F7IcM9EE3C4|website=YouTube|access-date=17 June 2017}}</ref>
==Personal life== Freedhoff married Stephen Freedhoff when she was around 20.<ref name="Weighty Matters obit" /> Stephen Freedhoff had graduated with a bachelor of commerce from the University of Toronto in 1957, going on to a career as a chartered accountant and consultant.<ref name="Stephen Freedhoff bio">{{cite web|title=Alumni Profiles - Rotman Commerce|url=https://rotmancommerce.utoronto.ca/alumni/profiles/|website=Rotman Commerce|publisher=University of Toronto|access-date=17 June 2017|archive-url=https://web.archive.org/web/20170701040744/https://rotmancommerce.utoronto.ca/alumni/profiles/|archive-date=1 July 2017}}</ref> They had a daughter, Michal Ilana Freedhoff, a son, Yoni Freedhoff, and seven grandchildren.<ref name="Weighty Matters obit" /> Michal Freedhoff gained a doctorate in solid state chemistry,<ref name="Michal - dissertation">{{cite book|last1=Freedhoff|first1=Michal Ilana|title=Quantum Confinement Effects on Semiconductor Nanocrystals: Direct, Direct Forbidden and Indirect Gap Materials|date=1995|publisher=University of Rochester|location=Rochester, NY|url=https://books.google.com/books?id=HsGmNwAACAAJ|access-date=17 June 2017}}</ref> and went on to serve as a US Congressional Science and Engineering Fellow in the office of Ed Markey.<ref name="Michal - EPA">{{cite web |title=About the Assistant Administrator of the Office of Chemical Safety and Pollution Prevention (OCSPP) Michal Ilana Freedhoff |url=https://www.epa.gov/aboutepa/about-assistant-administrator-office-chemical-safety-and-pollution-prevention-ocspp |archive-url=https://archive.today/20250115003901/https://www.epa.gov/aboutepa/about-assistant-administrator-office-chemical-safety-and-pollution-prevention-ocspp |archive-date=January 15, 2025 |website=epa.gov |publisher=US Environmental Protection Agency |access-date=10 June 2022}}</ref> She subsequently worked in a variety of government environmental protection roles, and was appointed Assistant Administrator for the Office of Chemical Safety and Pollution Prevention (OCSPP) of the US Environmental Protection Agency (EPA) in 2021.<ref name="Michal - EPA" /> Yoni Freedhoff is an associate professor of Family Medicine at the University of Ottawa and author.<ref name="YF UofO">{{cite web|title=Yoni Freedhoff|url=https://uniweb.uottawa.ca/#!/members/2310/profile|website=uniweb.uottawa.ca|publisher=University of Ottawa|access-date=17 June 2017|language=en}}</ref><ref name="Weighty Matters obit" /> Helen Freedhoff's personal pastimes included reading, playing piano, solving KenKen puzzles, and yoga.<ref name="Weighty Matters obit" />
Helen Freedhoff died suddenly on 10 June 2017 at the family's cottage in Muskoka, Ontario, a lakeside area near Toronto.<ref name="Obit Globe and Mail">{{cite news|title=Freedhoff (nee Goodman)|url=https://www.legacy.com/ca/obituaries/theglobeandmail/name/helen-freedhoff-obituary?pid=190003973|work=Globe and Mail (Legacy.com archive)|date=12 June 2017|language=en-ca}}</ref>
==Selected publications==
* W.R. Bruce, M.L. Pearson, Helen S. Freedhoff. The Linear Energy Transfer Distributions Resulting from Primary and Scattered X-Rays and Gamma Rays with Primary HVL's from 1.25 mm Cu to 11 mm Pb. ''Radiation Research'', 19 (4): 606-620.<ref name="Bruce et al 1963">{{cite journal|last1=Bruce|first1=W. R.|last2=Pearson|first2=M. L.|last3=Freedhoff|first3=Helen S.|title=The Linear Energy Transfer Distributions Resulting from Primary and Scattered X-Rays and Gamma Rays with Primary HVL's from 1.25 mm Cu to 11 mm Pb|journal=Radiation Research|date=August 1963|volume=19|issue=4|page=606|doi=10.2307/3571481|bibcode=1963RadR...19..606B|jstor=3571481}}</ref> * Helen Freedhoff, J. Van Kranendonk (1967). Theory of coherent resonant absorption and emission at infrared and optical frequencies. ''Can. J. Physics'', 45(5): 1833-1859.<ref name="HSF & JVK 1967">{{cite journal|last1=Freedhoff|first1=Helen|last2=Kranendonk|first2=J. Van|title=Theory of Coherent Resonant Absorption and Emission at Infrared and Optical Frequencies|journal=Canadian Journal of Physics|date=May 1967|volume=45|issue=5|pages=1833–1859|doi=10.1139/p67-142|bibcode=1967CaJPh..45.1833F}}</ref> * Helen S. Freedhoff (1979). Collective atomic effects in resonance fluorescence: Dipole-dipole interaction. ''Phys. Rev. A'' 19, 1132.<ref name="HSF 1979">{{cite journal|last1=Freedhoff|first1=Helen S.|title=Collective atomic effects in resonance fluorescence: Dipole-dipole interaction|journal=Physical Review A|date=1 March 1979|volume=19|issue=3|pages=1132–1139|doi=10.1103/PhysRevA.19.1132|bibcode=1979PhRvA..19.1132F}}</ref> * Helen S. Freedhoff (1982). Collective atomic effects in resonance fluorescence: The "scaling factor". ''Phys. Rev. A'' 26, 684.<ref name="HSF 1982">{{cite journal|last1=Freedhoff|first1=Helen S.|title=Collective atomic effects in resonance fluorescence: The "scaling factor"|journal=Physical Review A|date=1 July 1982|volume=26|issue=1|pages=684–688|doi=10.1103/PhysRevA.26.684|bibcode=1982PhRvA..26..684F}}</ref> * Helen Freedhoff, Zhidang Chen (1990). Resonance fluorescence of a two-level atom in a strong bichromatic field. ''Phys. Rev. A'' 41, 6013.<ref name="HSF & Chen 1990">{{cite journal|last1=Freedhoff|first1=Helen|last2=Chen|first2=Zhidang|title=Resonance fluorescence of a two-level atom in a strong bichromatic field|journal=Physical Review A|date=1 June 1990|volume=41|issue=11|pages=6013–6022|doi=10.1103/PhysRevA.41.6013|pmid=9903004|bibcode=1990PhRvA..41.6013F}}</ref> * Tran Quang, Helen Freedhoff (1993). Index of refraction of a system of strongly driven two-level atoms. ''Phys. Rev. A'' 48, 3216.<ref name="Quang & HSF 1993">{{cite journal|last1=Quang|first1=Tran|last2=Freedhoff|first2=Helen|title=Index of refraction of a system of strongly driven two-level atoms|journal=Physical Review A|date=1 October 1993|volume=48|issue=4|pages=3216–3218|doi=10.1103/PhysRevA.48.3216|pmid=9909976|bibcode=1993PhRvA..48.3216Q}}</ref> * Helen Freedhoff (2004). Evolution in time of an N-atom system. I. A physical basis set for the projection of the master equation. ''Physical Review A''. 69 (1).<ref name="HSF 2004">{{cite journal|last1=Freedhoff|first1=Helen|title=Evolution in time of an N-atom system. I. A physical basis set for the projection of the master equation|journal=Physical Review A|date=23 January 2004|volume=69|issue=1|article-number=013814|doi=10.1103/PhysRevA.69.013814|bibcode=2004PhRvA..69a3814F}}</ref>
==References== {{Reflist|30em}}
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{{DEFAULTSORT:Freedhoff, Helen}} Category:1940 births Category:2017 deaths Category:Canadian women physicists Category:Jewish Canadian physicists Category:Scientists from Toronto Category:Theoretical physicists Category:University of Toronto alumni