
Corrections to Solution to Problems for Student Friendly Quantum Field Theory

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Significant Corrections (may impact learning process)
Pg 
Date Posted 
Significant Correction 
Reported by (blank = the author) 
11 
Oct 13, 2017 
Prob. 6 statement of problem, 2^{nd} line: before “determine”, insert  assuming p_x is a single term  
Harm van der Lek 
12 
Oct 13, 2017 
Prob. 6, 4^{th} line below (C): Change “zero” to something other than ihbar times psi 
Michael Heiss 
21 
Aug 27, 2015 
Prob 1: “kgm^{2}/s” should be kgm/s^{2} 
Tom Bartholet 
23 
Sept 28, 2016 
Prob. 8, answer. after 2^{nd} arrow, insert x_{1}= x^{1}, x_{2}= x^{2}, x_{3}= x^{3}. Change x_{i }= x ^{j} to an arrow followed by x_{i }= x ^{i}. Then change v_{i }= v ^{j} to v_{i }= v ^{i} and p_{i }= p ^{j} to p_{i }= p ^{i} 
Tom Bartholet 
32 
Jan 17, 2015 
Prob. 3: Change “(327” to (325) (Same change in text pg. 82, Prob. 3). 
Michael Heiss 
34 
Aug 7, 2015 
Prob. 8: Third line up from bottom. should be and should be 
Stephen Palzewicz 
36 
Oct 11, 2016 
Prob. 12. Some “short cuts” I took in one or two steps in the derivation weren’t valid. The corrected solution is at Corrected Ch03 prob 12 
Jeroen Spandaw 
37 
June 12, 2015 
Prob. 13. The correction to a wrong sign in the solution in the booklet led to a few more steps in the derivation. See the revision of problem 313 solution. 
Tyler Antony 
39 
Mar 2, 2016 
Prob. 18, 2^{nd} line after “Thus”. “(factor)0>” should be (factor)phibar>  
Tom Bartholet 
46 
May 16, 2016 
Prob. 9. 1st line of answer, after last equal sign: the under bracket comments are true for p not = 0. If p = 0, then the first factor is zero and the second is V (volume). 
Tom Bartholet 
46 
May 16, 2016 
Prob. 9. . 2^{nd} line of answer, after 2^{nd} equal sign: exponent on 2^{nd} e should have a plus, not minus, sign. 
Tom Bartholet 
47 
Apr 23, 2015 
Prob. 10: In the phibar^{(3)} eq, the “ip^{2}” should have a minus, not plus sign in front. 
John Davidson 
411 
May 16, 2016 
Prob. 18, answer (second part), 1^{st} line: Under bracket “next page” should be below . 
Tom Bartholet 
413 
May 16, 2016 
Prob. 20, answer (second part), 2^{nd} line: p^{1}/p^{1} should be p^{1}/p^{1} and after the last equal sign should have +/ . As given the answer assumed only p^{1} positive. (third part): Same as above but for p^{3}/p^{3}. 
Tom Bartholet 
416 and 417 
May 16, 2016 
Prob. 27. 2^{nd} and 3^{rd} lines in answer: u_{r} should have r’. Next equation line on pg. 417: u_r(p) v_r’ dagger(p) should be ) v^r dagger (p) u_r’(p). Underbracket for that term should say “= 0 from the complex conjugate transpose of (425) RHS” 
Tom Bartholet 
420 
May 16, 2016 
Prob. 30. 4^{th} line up from bottom for i not = j: After 5^{th} equal sign, alpha_j beta alpha_i beta is better expressed as its mathematical equivalent beta alpha_j beta alpha_i. 
Tom Bartholet 
53 
June 16, 2016 
Prob. 6. Quicker ans. (first part), 1^{st} and 3^{rd} lines (two places). ((omega_k)^{2} k^{2}) should be (k^{2} (omega_k)^{2} ) 
Tom Bartholet 
67 
June 4, 2018 and Apr 23, 2015 
Prob. 14: See corrections in yellow in text (referencing corrections in some eqs) of Correction_Ch06_prob_14. Some factors exponential in time were left out, plus V in some denominators needed to be deleted. (Updated to include a subsequent correction reported on June 4 2018.) 
John Davidson and Sayan Datta 
71 
Aug 21, 2017 
Prob. 2. Replace s^mu with  ej^mu. (Note minus sign in front of e.) 6 places. 
Ian Marshall 
77 
Nov 11, 2016 
Prob. 13. In the next to last equation, which has “from (4146)” on the RHS: There should be a minus sign in front of iS_{F }(x_{1} x_{2}) and just below that a minus sign in front of psi (x_{1})psibar (x_{2}) 
Tom Bartholet 
81 
Dec 8, 2016 
Prob. 1. (Ans. (first part): Sentence beginning “Destruction operators …” should have double prime on r subscript and r after i). Sentence beginning “The remaining..”, the operator should be c_{r}dagger instead of adagger. (Ans. second part): delta function to left of Feynman diagram should have argument (p_{2}  k_{1} p_{1}). Eliminate the next line with equation. In last sentence, Eliminate “Note from the line before the last above, that”. 
Tom Bartholet 
82 
Dec 8, 2016 
Prob. 2. The delta function just above and to the left of the Feynman diagram should have the argument (p_{1} + p_{2} k) 
Tom Bartholet 
84 
May 9, 2017 
Prob. 5. Next to last line at bottom of the page: All brackets are anticommutators and need “+” as subscript on the right. 
Tom Bartholet 
86 
May 9, 2017 
Prob. 6. Eqs (P68),: exponents  ipx_{1} and  i(ptilda)x_{2} should be positive not negative. (P69) and (P610): exponents ip’_{2}x_{1} and  ip’_{1}x_{2} should be positive, not negative. 2 places. 
Tom Bartholet and Ian Marshal 
86 
May 9, 2017 
Prob. 6. Eq (P610): D_{F mu nu} needs factor of “i” in front. 
Tom Bartholet 
87 
Dec 18, 2015 
Eq (P612): In front of g_{mu nu} insert “i”. Two places. 
Don McDonald 
811 
May 9, 2017 
Prob. 8, Eq (P814): Insert a Dirac delta function with argument (p’ + k’  p k) 
Tom Bartholet 
812 
May 9, 2017 
Prob. 9. Last line: Insert a Dirac delta function with argument 0. 
Tom Bartholet 
813 
Nov 25, 2014 
Prob. 11, 3^{rd} line: Change “Fig. 83” to Fig. 84 Prob. 11, 14^{th} line: Change “Fig. 83” to Fig. 84 

814 
May 9, 2017 
Prob. 13: The expression immediately following the sentence beginning “By rule 7,…” needs a minus sign in front of it. 
Tom Bartholet 
815 
May 9, 2017 
Prob. 14: The last line for S_{F}^{(2)} should have a Dirac delta function with argument zero outside the integral. 
Tom Bartholet 
92 
May 12, 2017 
Prob. 4: In the final equation, first row “  (p_{2}  k)” should be “( p_{2}  k)”. Thus, the two minus signs in the second row should be deleted. 
Tom Bartholet 
112 
June 13, 2017 
Prob. 3. In 2^{nd} line of equations, after 2^{nd} equal sign, before first A^mu insert partial^nu. 
Tom Bartholet 
113 
June 13, 2017 
Prob. 6. Last line of the equations, before “not equal” sign insert . 
Tom Bartholet 
123 
Aug 21, 2017 
Prob. 7, 2^{nd} line up from bottom: “alpha (6.0)” should be alpha (12.0)  
Tom Bartholet 
123 
Aug 21, 2017 
Prob 8, 3^{rd} line of equations: The term with factor “ln p/mu” should also have a factor “partial e(mu)/partial mu”. 
Tom Bartholet 
141 to 142 
June 26, 2015 
Prob. 3. Subscript C1 everywhere it shows up should be C2. 3 places: one in problem statement, two right at end of solution. 
Jimmy Snyder 
141 to 3 
Dec 7, 2017 
Probs. 3 and 4: All “e^{2} “ should have a subscript zero. 
Tom Bartholet 
144 
Dec 7, 2017 
Prob. 8: All “e^{2} “ should have a subscript zero. 
Tom Bartholet 
163 
Apr11, 2018 
Prob. 5, Ans (first part), eq (A): k^{2} should be k_{2} (3 places) 
Tom Bartholet 
172 
July 21, 2018 
Prob. 4: Equation (D) should have all primes and nonprimes switched except in the propagators. Same in (E). In the text below (D), it should also be noted that (A) and (B) also differ from (C) and (D) via a switching of primes and nonprimes. Above (E), equation (1782) should be (1777). 
Tom Bartholet 
Minor Corrections (should not impact learning process)
Pg 
Date Posted 
Minor Correction 
Reported by 

Apr 22, 2015 
I should have acknowledged Luc Longtin at the front of the booklet for contributing four valuable problems to the 2^{nd} edition that were not in the 1^{st}. 
Luc Longtin 
21 and 22 
June 23, 2014 
Prob. 4: First sentence at end, delete one period. 1^{st} line: superscript “alpha beta” on “g” should be smaller font size. Part c), remove period after first alpha subscript. 
Jimmy Snyder 
22 
Feb 24, 2018 
Prob. 4(b)(ii): Change the second occurrence of  ∂^{2}/∂X_{2}^{2}^{ }to  ∂^{2}/∂X_{3}^{2} 
Ian Marshall 
22 
Feb 24, 2018 
Prob. 4 (c)(i): Change the second occurrence of  ∂^{2}/∂X_{2}^{2}^{ }to ∂^{2}/∂X_{3}^{2}^{ }and change the second occurrence of  (X_{2})^{2}^{ }to  (X_{3})^{2} 
Ian Marshall 
24 
Sept 10, 2015 
4^{th} block up in LH column: Change “Hamiltonian’s” to Hamilton’s 
Tom Bartholet 
31 
Mar 2, 2016 
Prob 1. After (31),change “RHS of (31)” to RH relation shown above  
Tom Bartholet 
32 
June 18, 2015 
Prob. 3: Change “of negative unity” to is negative 

37 
Mar 2, 2016 
Prob. 13. In (336), LH relation, k everywhere should be k′ 
Tom Bartholet 
37 
Feb 24, 2018 
Prob. 13. Some typos corrected in solution link revision of problem 313 solution 
Ian Marshall 
38 
Aug 7, 2015 
Prob. 14, first line of answer: The ket is missing in two places on the RHS. 
Stephen Palzewicz 
38 
Nov 25, 2014 
align eq number (330) with other eq numbers 

45 
Nov 25, 2014 
Prob. 5, last line, add an “s” at the end of “follow”. 

47 
May 16, 2016 
Prob. 10, 2^{nd} line: Delete “(next page)” 

411 
May 16, 2016 
Prob. 22. In 4 places d/partial x^mu should be partial/partial x^mu. 
Tom Bartholet 
61 
May 16, 2016 
Prob. 1: Font too big in some places. 

54 
June 18, 2015 
Prob. 8. In the second line of the answer A^{mu}(x) should, on the RHS be summed over r and k. Ditto for wherever the relation appears on the subsequent line in the solution. 

64 
Nov 25, 2014 
Prob. 9: gamma symbol too large in places 

65 
Nov 25, 2014 
Prob. 10: Some equations have font size that is too big. 

65 
Nov 25, 2014 
Prob. 11: Some equations have font size that is too big. 

71 
June 19, 2015 
Probs. 1 and 2. Change “s” everywhere to “ e^{.}j “ 

73 
May 16, 2016 
Prob. 4 Wholeness Chart: next to last line: change “cords” to coords  

73 
Sept 22, 2016 
Prob. 4. Middle of Wholeness Chart. Reference to “Lorentz Gauge” should be Lorenz Gauge  
Tom Bartholet 
74 
Sept 22, 2016 
Prob. 6., second part, second line. In first underbrackets there should be a factor of square root of 2 from the action of the destruction operator on the ket with 2 particles. 
Tom Bartholet 
81 
Nov 25, 2014 
Figure on lower RH too large 

84 
Dec 8, 2016 
Prob. 4. In the next to last line, add “s” to “integration”; add “time” to “space”; delete “s” at end of “eliminates”. In the last line, put a minus sign in front of e^{2}. Change “that” to “where e” 
Tom Bartholet 
84 
May 9, 2017 
Prob. 5. last line at bottom of the page: Change “from” to similar to  
Tom Bartholet 
85 
May 9, 2017 
Prob 6. Eq (P64): “LH” should be LHS  
Tom Bartholet 
813 
May 9, 2017 
Prob. 10. 3^{rd} line down on page: Subscript on eqsilon of “r mu” should be mu, r  
Tom Bartholet 
814 
May 9, 2017 
Prob. 12: In four cases D_{mu nu} should be D_{Fmu nu} 
Tom Bartholet 
815 
Nov 25, 2014 
Prob 15: 1^{st} line: tighten up spacing on e^{ MPSetChAttrs('ch0031','ch1',[[4,1,2,0,0],[5,1,2,0,0],[7,1,3,0,0],[],[],[],[16,1,7,0,0]]) MPInlineChar(2) } and e^{+} 

818 
Dec 8, 2016 
Prob. 18 was added online Dec 8, 2016. Its solution: Plot should have straight lines at 45 degree angles to E and k^{1} axes, originating at origin. Yes the mass shell for massive particles asymptotically approaches that of a photon for high E. 
Tom Bartholet 
91 
May 16, 2016 
Prob. 2, 3^{rd} line. Delete “are”. 

93 
May 12, 2017 
Prob. 8: It may be less confusing, if in the figure and all text, we use k” (double prime) instead of k, since we used k in Prob. 7 for the incoming photon. (But maybe it is OK as is.) 
Tom Bartholet 
101 
May 24, 2017 
Prob. 1, 2^{nd} line: The quantity inside the bra should not be the complex conjugate of the quantity inside the ket, but the same thing. The bra notation implies the quantity shown inside, when expressed mathematically, has the complex conjugate taken. 
Tom Bartholet 
102 
Nov 25, 2014 
Header on page should read “Student Friendly QFT” 

131 
May 16, 2016 
Prob. 3. Last line on page. delete first “in”. change 2^{nd} “in” to for . 

131 
Oct 13, 2017 
Prob. 3: To the right of Fig. 132, after “are”, insert where we drop the + iepsilon in the denominators for simplicity  
Tom Bartholet 
132 
Oct 13, 2017 
Prob. 4: The 2^{nd} and 3^{rd} lines of the last equation need to have + iepsilon in the denominator. 
Tom Bartholet 
132 
Nov 25, 2014 
Header on page should read “Student Friendly QFT” 

141 to 3 
Dec 7, 2017 
Probs. 3 and 4: For each “e^{0 }”, the superscript zero should be a subscript. 
Tom Bartholet 
144 
Dec 7, 2017 
Prob. 7: “e^{0 }” in last line of solution: the superscript zero should be a subscript. 2 places. 
Tom Bartholet 
152 
June 26, 2015 
Prob. 4: mu nu superscripts should be subscripts 
Jimmy Snyder 
161 
May 16, 2016 
Prob. 1, 1^{st} line: before “adjoint”, insert first . Change “have” to has . 

161 
Apr 11, 2018 
Prob. 1: Right after Ans (second part): D_mu nu should be D_F mu nu. 
Tom Bartholet 
171 
June 26, 2015 
Prob. 2: “renormalization” should be normalization 
Jimmy Snyder 
173 
July 20, 2018 
Prob. 6: The subscripts alpha and beta on B_(e) should be superscripts. 
Tom Bartholet 
177 
June 26, 2015 
Prob. 11, last line: after “COM”, insert frame 
Jimmy Snyder 